bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety Signals in the Primate Amygdala
Authors: Genud-Gabai Rotem , Klavir Oded , Paz Rony
Published: November 2013

The ability to distinguish danger from safety is crucial for survival. On the other hand, anxiety disorders can result from failures to dissociate safe cues from those that predict dangerous outcomes. The amygdala plays a major role in learning and signaling danger, and recently, evidence accumulates that it also acquires information to signal safety. Traditionally, safety is explored by paradigms that change the value of a previously dangerous cue, such as extinction or reversal; or by paradigms showing that a safe cue can inhibit responses to another danger-predicting cue, as in conditioned-inhibition. In real-life scenarios, many cues are never paired or tested with danger and remain neutral all along. A detailed study of neural responses to unpaired conditioned-stimulus (CS−) can therefore indicate whether information on safety-by-comparison is also acquired in the amygdala. We designed a multiple-CS study, with CS− from both visual and auditory modalities. Using discriminative aversive-conditioning, we find that responses in the primate amygdala develop for CS− of the same modality and of a different modality from that of the aversive CS+. Moreover, we find that responses are comparable in proportion, sign (increase/decrease), onset, and magnitude. These results indicate that the primate amygdala actively acquires signals about safety, and strengthen the hypothesis that failure in amygdala processing can result in failure to distinguish dangerous cues from safe ones and lead to maladaptive behaviors.
Gpr126 Functions in Schwann Cells to Control Differentiation and Myelination via G-Protein Activation
Authors: Mogha Amit , Benesh Andrew E. , Patra Chinmoy , Engel Felix B. , Schöneberg Torsten , Liebscher Ines , Monk Kelly R.
Published: November 2013

The myelin sheath surrounding axons ensures that nerve impulses travel quickly and efficiently, allowing for the proper function of the vertebrate nervous system. We previously showed that the adhesion G-protein-coupled receptor (aGPCR) Gpr126 is essential for peripheral nervous system myelination, although the molecular mechanisms by which Gpr126 functions were incompletely understood. aGPCRs are a significantly understudied protein class, and it was unknown whether Gpr126 couples to G-proteins. Here, we analyzeDhhCre;Gpr126fl/flconditional mutants, and show that Gpr126 functions in Schwann cells (SCs) for radial sorting of axons and myelination. Furthermore, we demonstrate that elevation of cAMP levels or protein kinase A activation suppresses myelin defects inGpr126mouse mutants and that cAMP levels are reduced in conditionalGpr126mutant peripheral nerve. Finally, we show that GPR126 directly increases cAMP by coupling to heterotrimeric G-proteins. Together, these data support a model in which Gpr126 functions in SCs for proper development and myelination and provide evidence that these functions are mediated via G-protein-signaling pathways.
Global Facilitation of Attended Features Is Obligatory and Restricts Divided Attention
Authors: Andersen Søren K. , Hillyard Steven A. , Müller Matthias M.
Published: November 2013

In many common situations such as driving an automobile it is advantageous to attend concurrently to events at different locations (e.g., the car in front, the pedestrian to the side). While spatial attention can be divided effectively between separate locations, studies investigating attention to nonspatial features have often reported a “global effect”, whereby items having the attended feature may be preferentially processed throughout the entire visual field. These findings suggest that spatial and feature-based attention may at times act in direct opposition: spatially divided foci of attention cannot be truly independent if feature attention is spatially global and thereby affects all foci equally.

In two experiments, human observers attended concurrently to one of two overlapping fields of dots of different colors presented in both the left and right visual fields. When the same color or two different colors were attended on the two sides, deviant targets were detected accurately, and visual-cortical potentials elicited by attended dots were enhanced. However, when the attended color on one side matched the ignored color on the opposite side, attentional modulation of cortical potentials was abolished. This loss of feature selectivity could be attributed to enhanced processing of unattended items that shared the color of the attended items in the opposite field. Thus, while it is possible to attend to two different colors at the same time, this ability is fundamentally constrained by spatially global feature enhancement in early visual-cortical areas, which is obligatory and persists even when it explicitly conflicts with task demands.
Fast Hemodynamic Responses in the Visual Cortex of the Awake Mouse
Authors: Pisauro M. Andrea , Dhruv Neel T. , Carandini Matteo , Benucci Andrea
Published: November 2013

Hemodynamic responses in mice and other species are typically measured under anesthesia. However, anesthesia could influence their relationship to neural activity. To investigate this relationship, we used optical imaging in mouse primary visual cortex (V1). Hemodynamic responses yielded clear maps of retinotopy in both anesthetized and awake mice. However, during wakefulness, responses were four times larger and twice as fast. These differences held whether we induced anesthesia with urethane or isoflurane and whether awake mice were stationary or running on a treadmill. With electrode recordings, we established that the effects of wakefulness reflect changes in neurovascular coupling, not in neural activity. By activating V1 directly via optogenetics, we replicated the effects of wakefulness in terms of timing but not of amplitude. We conclude that neurovascular coupling depends critically on anesthesia and wakefulness: during wakefulness, neural activity is followed by much stronger and quicker hemodynamic responses.
Preparing for Selective Inhibition within Frontostriatal Loops
Authors: Smittenaar Peter , Guitart-Masip Marc , Lutti Antoine , Dolan Raymond J.
Published: November 2013

Action inhibition can globally prevent all motor output or selectively cancel specific actions during concurrent motor output. Here we examine the behavioral and neural basis of selective inhibition focusing on the role of preparation. In 18 healthy human participants we manipulated the extent to which they could prepare for selective inhibition by providing or withholding information on what actions might need to be stopped. We show that, on average, information improves both speed and selectivity of inhibition. Functional magnetic resonance imaging data show that preparation for selective inhibition engages the inferior frontal gyrus, supplementary motor area, and striatum. Examining interindividual differences, we find the benefit of proactive control to speed and selectivity of inhibition trade off against each other, such that an improvement in stopping speed leads to a deterioration of selectivity of inhibition, and vice versa. This trade-off is implemented through engagement of the dorsolateral prefrontal cortex and putamen. Our results suggest proactive selective inhibition is implemented within frontostriatal structures, and we provide evidence that a speed-selectivity trade-off might underlie a range of findings reported previously.
Early Auditory Processing in Area V5/MT+ of the Congenitally Blind Brain
Authors: Watkins Kate E. , Shakespeare Timothy J. , O'Donoghue M. Clare , Alexander Iona , Ragge Nicola , Cowey Alan , Bridge Holly
Published: November 2013

Previous imaging studies of congenital blindness have studied individuals with heterogeneous causes of blindness, which may influence the nature and extent of cross-modal plasticity. Here, we scanned a homogeneous group of blind people with bilateral congenital anophthalmia, a condition in which both eyes fail to develop, and, as a result, the visual pathway is not stimulated by either light or retinal waves. This model of congenital blindness presents an opportunity to investigate the effects of very early visual deafferentation on the functional organization of the brain. In anophthalmic animals, the occipital cortex receives direct subcortical auditory input. We hypothesized that this pattern of subcortical reorganization ought to result in a topographic mapping of auditory frequency information in the occipital cortex of anophthalmic people. Using functional MRI, we examined auditory-evoked activity to pure tones of high, medium, and low frequencies. Activity in the superior temporal cortex was significantly reduced in anophthalmic compared with sighted participants. In the occipital cortex, a region corresponding to the cytoarchitectural area V5/MT+ was activated in the anophthalmic participants but not in sighted controls. Whereas previous studies in the blind indicate that this cortical area is activated to auditory motion, our data show it is also active for trains of pure tone stimuli and in some anophthalmic participants shows a topographic mapping (tonotopy). Therefore, this region appears to be performing early sensory processing, possibly served by direct subcortical input from the pulvinar to V5/MT+.
CRMP2 Tethers Kainate Receptor Activity to Cytoskeleton Dynamics during Neuronal Maturation
Authors: Marques Joana M. , Rodrigues Ricardo J. , Valbuena Sergio , Rozas Jose L. , Selak Sanja , Marin Philippe , Aller Maria I. , Lerma Juan
Published: November 2013

The CRMP2 and CRMP4 proteins are strongly expressed in the developing nervous system, mediating neurite outgrowth, neuronal polarity, and axon guidance. In the present study, we demonstrate the interaction of the CRMP2 and CRMP4 proteins with the GluK5 subunit of the kainate (KA) receptor (KAR) and investigated the role of KARs in modulating the development of cultured mouse DRG neurons. We found that KARs modulate neuronal maturation and neurite outgrowth in a bidirectional manner. Accordingly, low concentrations of KA delayed maturation and enhanced neurite outgrowth, whereas maturation was promoted by higher concentrations of KA that attenuated neuritic elongation. The effects of weak KAR activation were prevented by blocking their noncanonical signaling and involved a differential regulation of CRMP2. Whereas the delay in maturation involves PKC-mediated phosphorylation of CRMP2 at T555 leading to a downregulation of membrane Cav2.2, the promotion of neurite outgrowth is achieved by dephosphorylation at T514 at the growth cones, the latter reflecting PKC-driven enhancement of GSK3β phosphorylation at S9. Together, these findings indicate that noncanonical KAR signaling influences neuronal development by modulating CRMP2 activity.
α6β1 and α7β1 Integrins Are Required in Schwann Cells to Sort Axons
Authors: Pellegatta Marta , De Arcangelis Adèle , D'Urso Alessandra , Nodari Alessandro , Zambroni Desirée , Ghidinelli Monica , Matafora Vittoria , Williamson Courtney , Georges-Labouesse Elisabeth , Kreidberg Jordan , Mayer Ulrike , McKee Karen K. , Yurchenco Peter D. , Quattrini Angelo , Wrabetz Lawrence , Feltri Maria Laura
Published: November 2013

During development, Schwann cells extend lamellipodia-like processes to segregate large- and small-caliber axons during the process of radial sorting. Radial sorting is a prerequisite for myelination and is arrested in human neuropathies because of laminin deficiency. Experiments in mice using targeted mutagenesis have confirmed that laminins 211, 411, and receptors containing the β1 integrin subunit are required for radial sorting; however, which of the 11 α integrins that can pair with β1 forms the functional receptor is unknown. Here we conditionally deleted all the α subunits that form predominant laminin-binding β1 integrins in Schwann cells and show that only α6β1 and α7β1 integrins are required and that α7β1 compensates for the absence of α6β1 during development. The absence of either α7β1 or α6β1 integrin impairs the ability of Schwann cells to spread and to bind laminin 211 or 411, potentially explaining the failure to extend cytoplasmic processes around axons to sort them. However, double α6/α7 integrin mutants show only a subset of the abnormalities found in mutants lacking all β1 integrins, and a milder phenotype. Double-mutant Schwann cells can properly activate all the major signaling pathways associated with radial sorting and show normal Schwann cell proliferation and survival. Thus, α6β1 and α7β1 are the laminin-binding integrins required for axonal sorting, but other Schwann cell β1 integrins, possibly those that do not bind laminins, may also contribute to radial sorting during peripheral nerve development.
The Agenda-Setting Power of Stakeholder Media
Authors: Hunter Mark Lee , Van Wassenhove Luk N. , Besiou Maria , van Halderen Mignon
Published: November 2013

Media controlled by stakeholder communities and groups, or “stakeholder media,” can exercise powerful influence on the strategic agendas of firms. Stakeholder media can be different and in some ways stronger than the influence of traditional news media. This article identifies strategies through which stakeholder groups use their own media to achieve desired outcomes, as support for or extensions of strategies known from the literature on social movements. These strategies rely on specific characteristics of stakeholder media that differ from mainstream media. These communication tools have altered the dynamics of stakeholder influence: on the one hand, allowing them greater independence from and influential collaboration with mainstream media as well as with other stakeholders; and on the other, augmenting the scope and momentum of their adversarial campaigns. There are important risks and opportunities posed to organizations by stakeholder media.
Where Has the Time Gone? Addressing Collaboration Overload in a Networked Economy
Authors: Cross Rob , Gray Peter
Published: November 2013

As a result of the spread of social media and collaboration technologies in the workplace, the adoption of matrix-based structures, and the proliferation of initiatives to create a “one firm” culture, many organizations are experiencing collaboration overload. Too often, excessive collaboration harms organizational performance, overworking employees for only marginal gains. High-performing employees are especially vulnerable because they already shoulder a disproportionate collaboration burden. This article shows how traditional approaches to improving collaboration often invisibly slow decision making and hurt performance, and describes how companies can identify and address points of collaboration overload and use structural and behavioral interventions to streamline information-sharing and decision-making interactions.
Pesquisa translacional em diabetes melito gestacional e hiperglicemia gestacional leve: conhecimento atual e nossa experiência
Authors: Rudge Marilza Vieira Cunha , Piculo Fernanda , Marini Gabriela , Damasceno Débora Cristina , Calderon Iracema Mattos Paranhos , Barbosa Angélica Pascon
Published: November 2013

O diabetes materno constitui um ambiente desfavorável para o desenvolvimento embrionário e feto-placentário. É uma repercussão de importância na obstetrícia moderna, visto que está associado a um risco aumentado de morbidade materna e neonatal e continua a ser um desafio médico significativo. O aumento mundial na incidência do diabetes, o aumento do diabetes tipo 2 em mulheres em idade reprodutiva e a geração cruzada da programação intrauterina do diabetes tipo 2 são as bases para o interesse crescente na utilização de modelos experimentais diabéticos, a fim de obter conhecimento sobre os mecanismos que induzem as alterações de desenvolvimento no diabetes gestacional. Vários estudos têm demonstrado os benefícios da prevenção do diabetes com intervenções no estilo de vida, melhora metabólica e controle de fator de risco cardiovascular para evitar substancialmente as complicações devastadores da doença. Apesar desses achados e a revolução recente no conhecimento científico e infinidade de novas terapias do diabetes, continua a haver uma grande lacuna entre o que foi aprendido por meio da pesquisa e o que é feito na prática da saúde pública, clínica e comunitária. O iminente impacto econômico negativo dessa complacência nos indivíduos, nas famílias e nas economias nacionais é alarmante. Espera-se que a pesquisa translacional no binômio diabetes-gravidez seja implementada em centros de excelência tanto de pesquisa básica como aplicada e complementada por estudos clínicos multicêntricos, conduzidos de forma pragmática para aumentar o nível de evidência científica com recursos diagnósticos e propedêuticos mais confiáveis.
Adsorção de Ni2+ e Zn2+ em argila calcinada: estudo de equilíbrio em coluna de leito fixo
Authors: Araujo A. L. P. de , Nogueira I. L. , Silva M. G. C. Da , Gimenes M. L. , Barros M. A. S. D. De
Published: November 2013

A aplicação de argilas para adsorção de metais pesados presentes em efluentes tem sido objeto de estudo em muitas pesquisas em virtude das inúmeras vantagens técnicas e econômicas. Este trabalho teve como objetivo obtenção de isotermas de adsorção de níquel e zinco em coluna de leito fixo utilizando como adsorvente argila bentonita calcinada a 500 ºC. Os experimentos para remoção de níquel e zinco foram conduzidos à temperatura ambiente (20 ºC - 25 ºC), pH da alimentação ajustado em 4,5, massa de argila calcinada de 15,5 g, com diâmetro médio de 0,855 mm, vazão de alimentação de 4 mL/min e concentração da solução de metal variando entre 0,5 meq/L a 4 meq/L. Os modelos de isoterma de Langmuir, Freundlich, Langmuir-Freundlich, Radke-Prausnitz, Redlich-Peterson, Sips e Toth foram ajustados aos dados de equilíbrio, sendo que o modelo de Langmuir apresentou melhor ajuste às concentrações de Ni2+ e Zn2+ adsorvido.
Effects of crystal ordering and composition on properties of CdSxTe1−x alloys: a first-principle insight
Authors: Chen Dongguo , Ravindra Nuggehalli M.
Published: November 2013

Effects of crystal ordering and composition on the properties of CdSxTe1−x alloys are studied using first-principle calculations. The authors find that the chalcopyrite structure with (201) ordering has the lowest formation energy. (110) Y2 ordering can occur in disordered structure due to the small energy difference. The authors find that the spin-orbit (SO) splitting, band gap and their bowing parameters are significantly dependent on the ordering and composition. For the compound CdS0·5Te0·5, negative bowing parameter of SO splitting is found in ordered structures, while positive bowing parameter is found in disordered structure. For a given (100) ordering, the bowing parameter of energy gap increases with the decreasing of the bowing parameter of SO splitting.
Consensus RDA across dissimilarity coefficients for canonical ordination of community composition data
Authors: Blanchet F. Guillaume , Legendre Pierre , Bergeron J. A. Colin , He Fangliang
Published: November 2013

Understanding how habitat structures species assemblages in a community is one of the main goals of community ecology. To relate community patterns to particular factors defining habitat conditions, ecologists often use canonical ordinations such as canonical redundancy analysis (RDA). It is a common practice to use dissimilarity coefficients to perform canonical ordinations through distance‐based RDA (db‐RDA) or transformation‐based RDA (tb‐RDA). Dissimilarity coefficients are measures of resemblance where the information about species communities is condensed into a symmetric square matrix of dissimilarities among sites. In this study, we compared 16 of the most commonly used dissimilarity coefficients to evaluate if the species‐abundance distribution (SAD) of a community can be used to select an appropriate coefficient. Of these, 11 are designed to be used primarily with abundance data, although they can also be used with presence–absence data, whereas five can only be applied to presence–absence data. Using simulations, we compared the explained variance of RDAs differing only by their coefficients to evaluate how the abundance patterns of communities influence coefficient choice. We found that coefficients are largely equivalent, independently of the community SAD. In light of these findings, we propose the consensus RDA method, a new canonical ordination procedure that performs a consensus of RDAs across several coefficients. This new method focuses on the common relations found by independent RDAs differing only by their dissimilarity coefficients; this ensures the absence of a coefficient‐related bias when interpreting the canonical ordination result. Also, because in our simulations the presence–absence data were directly derived from the abundance data, we were able to evaluate if the information in presence–absence data was equivalent to that in abundance data. We found that although some information was lost by converting abundance data into presence–absence, both data formats may be complementary. When applying consensus RDA to abundance and presence–absence data independently, a more complete understanding and interpretation of the ecological patterns is obtained. An ecological example illustrating consensus RDA and the conclusions of our simulations is presented, using Carabidae data collected at the Ecosystem Management Emulating Natural Disturbances (EMEND) project in northwestern Alberta, Canada.
Spectral Analysis of Prone-to-fall Rock Compartments using Ambient Vibrations
Authors: Bottelin Pierre , Jongmans Denis , Baillet Laurent , Lebourg Thomas , Hantz Didier , Lévy Clara , Le Roux Olivier , Cadet Héloïse , Lorier Lionel , Rouiller Jean-Daniel , Turpin Julien , Darras Lionel
Published: November 2013

The dynamic response of four unstable rock compartments in the Alps has been studied using the ambient vibration technique, with the aim of identifying precursors to rockfalls. The test sites present various geological settings (limestone, argillite, and shale-sandstone series), failure mechanisms and volumes. The ambient vibration spectra measured on the unstable compartments systematically showed clear energy peaks at specific frequencies, in contrast with records made on the adjacent stable rock masses. These predominant frequencies were interpreted as resonant frequencies of the unstable compartments, in agreement with 2-D modal analysis. In the horizontal plane, ground motion at the fundamental frequency was found to be systematically parallel to the line of maximum slope gradient, and perpendicular to the main bounding fracture observed at most of the sites. The fundamental frequency of each prone-to-fall compartment shows reversible variations related to temperature fluctuations at different timescales, with a significant contrast in magnitude and phase shift between sites. At the more fractured site, resonance seems to result from a contrast in internal rigidity between the compartment and adjacent rock mass, rather than from decoupling along a rear fracture, which is the mechanism observed at the three other sites. No change in fundamental frequency resulting from damage was observed over the period of study.
Slidequake Generation versus Viscous Creep at Softrock-landslides: Synopsis of Three Different Scenarios at Slumgullion Landslide, Heumoes Slope, and Super-Sauze Mudslide
Authors: Walter Marco , Gomberg Joan , Schulz William , Bodin Paul , Joswig Manfred
Published: November 2013

In this study, we describe conditions for slidequake generation at three different creeping softrock landslides: the Slumgullion landslide in the San Juan Mountains, Colorado, U.S., the Heumoes slope in the Austrian Alps, and the mudslide in Super-Sauze, French Alps. From a geomorphologic point of view, all three landslides are classified as creeping landslides with average velocities between centimeters to meters per year. Associating creep with viscous flow, and considering the largely saturated, clayey consistency of the slope body, one would not expect any brittle behavior. Thus, it came as a surprise that impulsive seismic signals indicative of shear fracture could be discovered by sensitive passive monitoring methods at all three slopes. These fracture signals occur in episodes, have similar signatures as small earthquakes, and could be located within the slide bodies, i.e., are evidence of slidequakes.

Our investigations identified seismic and aseismic slip in each slide, with slidequakes focusing at significant bedrock structures or at lateral boundaries. Synoptic comparison of three scenarios underlines the importance of landslide-bedrock and landslide-lateral boundary interactions under gravitational loading and Mohr-Coulomb-type failure. Comparison to frictional and asperity models of crustal- and plate-scale boundaries may pave the way to a comprehensive understanding of slidequake generation, and future slope failure prediction.
Metagenomes obtained by ‘deep sequencing’ – what do they tell about the enhanced biological phosphorus removal communities?
Authors: Albertsen Mads , Saunders Aaron M. , Nielsen Kåre L. , Nielsen Per H.
Published: November 2013

Metagenomics enables studies of the genomic potential of complex microbial communities by sequencing bulk genomic DNA directly from the environment. Knowledge of the genetic potential of a community can be used to formulate and test ecological hypotheses about stability and performance. In this study deep metagenomics and fluorescence in situ hybridization (FISH) were used to study a full-scale wastewater treatment plant with enhanced biological phosphorus removal (EBPR), and the results were compared to an existing EBPR metagenome. EBPR is a widely used process that relies on a complex community of microorganisms to function properly. Insight into community and species level stability and dynamics is valuable for knowledge-driven optimization of the EBPR process. The metagenomes of the EBPR communities were distinct compared to metagenomes of communities from a wide range of other environments, which could be attributed to selection pressures of the EBPR process. The metabolic potential of one of the key microorganisms in the EPBR process, Accumulibacter, was investigated in more detail in the two plants, revealing a potential importance of phage predation on the dynamics of Accumulibacter populations. The results demonstrate that metagenomics can be used as a powerful tool for system wide characterization of the EBPR community as well as for a deeper understanding of the function of specific community members. Furthermore, we discuss and illustrate some of the general pitfalls in metagenomics and stress the need of additional DNA extraction independent information in metagenome studies.
Removal of phosphorus from wastewaters by biomass ashes
Authors: Barbosa R. , Lapa N. , Lopes H. , Morujo A. , Mendes B.
Published: November 2013

Removal batch assays of phosphates from a synthetic wastewater (SWW) and a pulp and paper mill wastewater (PPWW) with two forestry biomass ashes were performed. The supernatants were not only chemically characterized but also the ecotoxicity was determined using two organisms: Vibrio fischeri and Artemia franciscana. The addition of fly ash and bottom ash to the SWW in solid/liquid (S/L) ratios of 3.35 and 9.05 g L−1, respectively, achieved removal percentages of phosphates >97% for both ashes. The addition of fly ash and bottom ash to the PPWW in S/L ratios of 34.45 and 46.59 g L−1, respectively, yield removal percentages of phosphates >90% for both ashes. According to the results of the Langmuir and Freundlich isotherms, the removal of phosphates from the SWW was mainly explained by surface removal mechanisms, while the removal from the PPWW was partially explained by multi-layer mechanisms. The supernatants resulting from the treatment of SWW and PPWW with both biomass ashes did not present acute ecotoxicity.
Enamel Reduction Techniques in Orthodontics: A Literature Review
Authors: Livas Christos , Jongsma Albert Cornelis , Ren Yijin
Published: November 2013

Artificial abrasion of interproximal surfaces has been described for almost seventy years as orthodontic intervention for achievement and maintenance of ideal treatment outcome. A variety of terms and approaches have been introduced throughout this period implying a growing clinicians’ interest. Nevertheless, the widespread recognition of enamel stripping technique was initiated by the advent of bonded orthodontic attachments and a 2-article series of Sheridan in the 80’s. Since then, experimental and clinical research has been focused on the investigation of instrumentation efficacy and potential iatrogenic sequelae related to interproximal stripping. This review discusses the evolution, technical aspects and trends of enamel reduction procedures as documented in the literature.
Polypoidal Choroidal Vasculopathy – A Type I Polypoidal Subretinal Neovasculopathy
Authors: Kokame Gregg T
Published: November 2013

This 47 year old female developed the new onset of a polypoidal subretinal neovascular membrane in the left eye 13 years after having polypoidal choroidal vasculopathy (PCV) treated in the right eye. The indocyanine green (ICG) angiography of the left eye at initial presentation showed a normal choroidal vascular pattern without PCV. The new development of a PCV complex on ICG angiography demonstrates that PCV is truly a type of subretinal neovascularization, and not a choroidal vascular abnormality. The optical coherence tomography shows that the polypoidal vascular complex lies above Bruch’s membrane and beneath the retinal pigment epithelium, and not within the choroid. Treatment with high dose ranibizumab (2.0 mg) resulted in excellent polyp closure and regression of the branching vascular network. The documented new development of polypoidal subretinal vessels on ICG angiography and the response to ranibizumab supports that PCV is a polypoidal neovasculopathy (PNV).
Numerical analysis of mixed convection in pulsating flow for a horizontal channel with a cavity heated from below
Authors: Selimefendigil Fatih
Published: November 2013

In this study, a channel with a cavity heated from below is numerically
investigated for the mixed convection case in pulsating flow for a range of
Richardson numbers (Ri=0.1, 1, 10, 100) at Reynolds number of 50 in the
laminar flow regime. At the inlet of the channel, pulsating velocity is
imposed for Strouhal numbers between 0.1 to 1 and velocity amplitude ratio
between 0.3 to 0.9. The effect of the pulsation frequency, amplitude and
Richardson number on the heat transfer enhancement is numerically analyzed.
The results are presented in terms of streamlines, isotherm plots and
averaged Nusselt number plots. FFT plots for the Nusselt number response to
single sinusoidal velocity forcing at the inlet and nonlinearity in the
response is also provided.
The Mammalian INDY Homolog Is Induced by CREB in a Rat Model of Type 2 Diabetes
Authors: Neuschäfer-Rube Frank , Lieske Stefanie , Kuna Manuela , Henkel Janin , Perry Rachel J. , Erion Derek M. , Pesta Dominik , Willmes Diana M. , Brachs Sebastian , von Loeffelholz Christian , Tolkachov Alexander , Schupp Michael , Pathe-Neuschäfer-Rube Andrea , Pfeiffer Andreas F.H. , Shulman Gerald I. , Püschel Gerhard P. , Birkenfeld Andreas L.
Published: November 2013

Reduced expression of the INDY (I'm not dead yet) tricarboxylate carrier increased the life span in different species by mechanisms akin to caloric restriction. Mammalian INDY homolog (mIndy, SLC13A5) gene expression seems to be regulated by hormonal and/or nutritional factors. The underlying mechanisms are still unknown. The current study revealed that mIndy expression and [14C]-citrate uptake was induced by physiological concentrations of glucagon via a cAMP-dependent and cAMP-responsive element–binding protein (CREB)–dependent mechanism in primary rat hepatocytes. The promoter sequence of mIndy located upstream of the most frequent transcription start site was determined by 5′-rapid amplification of cDNA ends. In silico analysis identified a CREB-binding site within this promoter fragment of mIndy. Functional relevance for the CREB-binding site was demonstrated with reporter gene constructs that were induced by CREB activation when under the control of a fragment of a wild-type promoter, whereas promoter activity was lost after site-directed mutagenesis of the CREB-binding site. Moreover, CREB binding to this promoter element was confirmed by chromatin immunoprecipitation in rat liver. In vivo studies revealed that mIndy was induced in livers of fasted as well as in high-fat-diet–streptozotocin diabetic rats, in which CREB is constitutively activated. mIndy induction was completely prevented when CREB was depleted in these rats by antisense oligonucleotides. Together, these data suggest that mIndy is a CREB-dependent glucagon target gene that is induced in fasting and in type 2 diabetes. Increased mIndy expression might contribute to the metabolic consequences of diabetes in the liver.
Guidelines for Thermographic Inspection of Concrete Bridge Components in Shaded Conditions
Authors: Washer Glenn , Fenwick Richard , Nelson Seth , Rumbayan Rilya
Published: November 2013

Infrared thermography has the potential to detect subsurface delaminations before spalling develops and could be used to improve the visual inspection of concrete bridges. The technology has traditionally been applied to bridge decks, which are exposed to radiant heating from the sun that helps develop the necessary thermal gradients in the concrete. Thermal gradients can also be developed from normal diurnal temperature variations. Convective heat transfer develops the thermal gradients, although these thermal gradients are of much lower magnitude than those developed through radiant heating from the sun. This paper presents the results of a study to develop thermal imaging for the detection of subsurface deterioration in the soffit areas of bridges; these soffit areas are shaded and therefore are not exposed to radiant heating from the sun. Experimental studies and field testing were conducted and are described. This paper reports on guidelines developed for this application of the technology; the guidelines address the necessary environmental conditions to enable the detection of damage in bridge soffit areas. Specifically, the paper discusses the rates of change in ambient temperature needed to ensure that subsurface damage can be detected in shaded conditions. The paper also discusses the effect of wind speed on the detectability of subsurface damage in the shaded areas of a bridge, as well as the camera settings needed to ensure that an inspector can detect temperature anomalies associated with subsurface damage. A field example is provided to illustrate the application of the technology and highlight the required camera settings.
Fatigue Testing and Structural Health Monitoring of Retrofitted Web Stiffeners on Steel Highway Bridges
Authors: Ghahremani Kasra , Sadhu Ayan , Walbridge Scott , Narasimhan Sriram
Published: November 2013

Numerous steel highway bridges, still in use today, were built during the construction boom between the late 1950s and the late 1970s. Fatigue cracking can be considered a main source of deterioration for these bridges. The largest category of observed fatigue cracks is caused by out-of-plane distortion. The most susceptible locations are those at which transverse structural components (such as diaphragms or cross frames) are framed into longitudinal girders through web stiffeners that are not attached to the flanges. In the current study, a web stiffener detail is fatigue tested under different cyclic loading conditions. As-welded specimens are tested, along with specimens retrofitted by grinding and rewelding, needle peening, or the adhesive bonding of fiber-reinforced polymer attachments. Direct strain and deflection measurements are compared with finite element analysis predictions, and local (hot-spot) stresses are compared with hot-spot stress design curves. A time series–based method for damage detection is also explored for the prediction of fatigue crack depth with strain data. The method is validated through the use of small- and large-scale specimen strain data. It is found that damage measures based on strains in the vicinity of the critical hot spot are closely correlated with the true crack depth.
Vulnerability Assessment of Bridges Exposed to Scour
Authors: Tanasić Nikola , Ilić Vladan , Hajdin Rade
Published: November 2013

To improve the allocation of funds for the maintenance and risk mitigation of transportation infrastructure, there is a dire need for a simplified, yet sufficiently accurate, methodology to estimate bridge vulnerability to scour. The methodology should make use of existing data and indicate the basic variables needed to assess the vulnerability of bridges located around a future expressway in southeastern Serbia. The first part of the paper discusses the identification of possible modes of bridge failure caused by scouring that depend on soil, structure, and river hydraulic properties. The degradation of soil parameters is assumed to be the main cause of bridge failure. The capacity of a bridge to withstand a certain amount of structural damage governs the direct and indirect costs attributable to bridge failure; the subsequent work zones related to rehabilitation reduce the performance of the whole network. In the second part of the paper, a simulation of the redistribution of traffic flows is described for several possible scenarios; the simulations use state-of-the-art software VISUM, which was developed for computer-aided transportation planning and analysis. The simulated scenarios include the partial and full closure of road links as a result of bridge failures. The simulations confirmed that the most significant contribution to indirect costs stems from the increase in the total travel time of all network users.
Development of Bridge Management Components that Facilitate Decision Making
Authors: Johnson Joshua F. , Ozbek Mehmet E.
Published: November 2013

Because of limited funds, a greater demand for use, and continuous deterioration, it is crucial that transportation agencies have effective decision-making processes and tools, such as bridge management systems, to manage agency bridge networks. Given the shortcomings of the current bridge management practices as repeatedly highlighted in the literature, it is evident that a decision process that only involves a single rating or index, such as the sufficiency rating or the bridge health index, is inadequate for bridge management. Therefore, there is a clear need to pursue and develop supplemental bridge management practices. The primary contribution of this research is to provide engineers, managers, and decision makers with effective bridge management components that have well-defined goals and related items. Additionally, these components clearly identify and distinguish differences in bridge attributes that may go unnoticed when a single criterion is used. Transportation agencies may use these bridge management components in a variety of ways to complement current bridge management practices; this usage may better illustrate the performance of the agencies’ bridges. The specific objectives of this research are (a) to identify the appropriate items that make up each of the aforementioned components and (b) to determine the relative importance of those items, as represented by weighting factors. To achieve these objectives, this research was conducted in two parts, and input was sought from key bridge management personnel, industry professionals, and academics. The first part consisted of a survey; the second part utilized a mathematical method entitled the analytic hierarchy process.
Development of Maintenance and Rehabilitation Program
Authors: Alyami Zaid , Tighe Susan L.
Published: November 2013

Over the past decade, there has been a movement in North America toward a performance-based contract (PBC) model for maintaining and managing road networks. In traditional method-based contracts, the owner agency specifies techniques, materials, methods, and quantities, along with the time period for the contract. By contrast, in a PBC, the client agency specifies certain clearly defined minimum performance measures to be met or exceeded during the contract period. PBC is a type of contract in which payments are explicitly linked to the contractor's successfully meeting or exceeding certain clearly defined minimum performance indicators. Therefore, the selection of a PBC model for maintenance and rehabilitation differs significantly from that of a traditional asset management contract. Also, a PBC is more complex because of the pavement deterioration process and probability of failure to achieve the specified level of service for various performance measures along the contract period. A novel framework was developed for the selection of maintenance and rehabilitation activities with a model for pavement performance prediction and linear optimization. A case study based on data from the second generation pavement management system of the Ministry of Transportation Ontario is used to illustrate the framework.
Identifying Optimal Highway Asset Maintenance on the Basis of Performance Targets and Budget Constraints
Authors: Galenko Alexander , Pilson Charles , Scheinberg Tonya
Published: November 2013

The majority of maintenance optimization literature is focused on pavement maintenance related to pavement management systems. The literature does not cover well the proper procedures for optimizing the full range of typical highway maintenance activities based on measurement and prediction of performance. In addition, practitioners are only now getting started in this area of maintenance optimization, in which they use software tools to aid in planning non-pavement—related maintenance. Although much of the optimization work to date focused on predicting deterioration explicitly over time, the method of maintenance optimization that is presented in this paper, called maintenance analysis, assumes a steady state is reached with regard to maintenance activities. This maintenance analysis method allows maintenance managers to use level of service and utility functions to define maintenance indices. With this method, managers are able to identify and plan the optimal mix of maintenance activities to (a) maximize performance with respect to maintenance performance indices based on user-defined budget constraints and (b) minimize cost based on level of service targets. A simple numerical example is presented to illustrate the method.
Development of Enhanced Alaska Pavement Preservation Program and Strategy Selection Guide
Authors: Cheng DingXin , Hicks R. Gary , Parsons Angela , Zubeck Hannele , Liu Jenny , Mullin Anthony
Published: November 2013

The Alaska Department of Transportation and Public Facilities (DOT&PF) wished to enhance its existing pavement preservation management program by using effective pavement preservation treatments for cold regions. This initiative would extend pavement life and defer the need for more costly rehabilitation. By collaborating with the California Pavement Preservation Center and the Alaska University Transportation Center, the Alaska DOT&PF recently completed a pavement preservation research project to improve its pavement preservation program for flexible pavements. Research tasks included conducting an international survey of pavement preservation in cold regions, reviewing literature on cold region pavement preservation treatments, monitoring existing preservation treatments that Alaska used, developing a pavement preservation database, and creating an online computer program for treatment selection. The database for pavement preservation treatment tracking is a web-based online program that includes standard types of pavement preservation strategies used in Alaska; pavement construction, traffic, weather, and other performance-related information; an integrated Google Map function to show the location of pavement preservation projects; and multiple pavement condition survey results with supporting documents. The strategy selection program is integrated within the pavement preservation database. The program sees results of the survey and other information on Alaska treatments to conduct treatment strategy selection and life-cycle cost analysis. Workshops have been given on preservation treatments used in cold regions and use of the database and strategy selection process. Tools developed for the Alaska DOT&PF should be helpful for long-term implementation of an effective pavement preservation program. Other agencies could learn from Alaska's experience.
Effects of Curing and Oxidative Aging on Raveling in Emulsion Chip Seals
Authors: Moraes Raquel , Bahia Hussain U.
Published: November 2013

Although chip seals have a proven history of performance, several distresses are commonly encountered in the field. The most common distresses in chip seals are flushing or bleeding and aggregate loss from the top layer (i.e., raveling). Raveling is not restricted to the early life of the chip seal, but continue throughout the service life. The current state of knowledge and testing of the mechanisms governing raveling in chip seals does not sufficiently account for the effects of in-service emulsion–aggregate bond maturation and oxidative aging on chip loss over the expected service life of the chip seal. Emulsion–aggregate adhesion was thought to control the early raveling process, while the residual asphalt binder rheological properties and aggregate embedment in the emulsion might contribute to later raveling in chip seals. Raveling of chip seals subjected to varying degrees of time–temperature conditioning was evaluated to account for different chemical and physical interactions at the aggregate–asphalt interface. Testing results showed that the rate of in-service raveling depended on the curing process and subsequent in-service oxidative aging as the adhesive and cohesive forces at the emulsion–aggregate interface changed. The initial bond maturation resulted in a decreased rate of chip loss, and the in-service oxidative aging of the asphalt emulsion led to a higher aggregate loss as a result of the emulsion's strain intolerance and inability to relax stresses induced by traffic.
Corrosion by Chloride Deicers on Highway Maintenance Equipment
Authors: Li Yongxin , Fang Yida , Seeley Nicholas , Jungwirth Scott , Jackson Emily , Shi Xianming
Published: November 2013

This work aimed to identify and evaluate best practices that could be implemented to minimize the corrosion of chloride deicers on winter application equipment and vehicles. Identified practices included design improvements, maintenance practices, anticorrosion coatings, corrosion inhibitors, salt removers, and so on. A nationwide survey was conducted to capture current knowledge about estimating the deicer corrosion costs to vehicles and equipment, defining the chloride deicer corrosion problem, and identifying best practices or products for managing the problem. For agencies that report deicer corrosion to equipment as a significant issue, the total cost of current corrosion management and corrosion risks related to deicer exposure was estimated to average $1.06 million and $14.05 million per year, respectively. On average, deicer exposure leads to risks in six areas: 17.3% depreciation in equipment value, 8.5% increase in equipment downtime, 11.9% reduction in equipment reliability, 17.3% reduction in equipment service life, 19.6% increase in premature repair and replacement, and 1.5% risk in safety from faulty parts on equipment. The survey identified four anticorrosion coating products, four spray-on corrosion inhibitors, and six salt removers as best products based on user experience. Subsequently, a screening test and a 2-week test with electrochemical impedance spectroscopy measurements were conducted to assess the effectiveness of the products in reducing the corrosion effect of magnesium chloride solution to carbon steel. Under the investigated conditions, the best-performing coating (Rust Bullet), inhibitor (Krown), and salt removers (HoldTight and ChlorRid) were identified. They all showed outstanding performance in corrosion protection.