bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface and borehole seismic imaging of soft-rock, karst eolianites at coastal engineering construction sites: Case studies from Australia
Authors: Whiteley Robert J.
Published: January 2012

Eolianite, dune calcarenite, or kurkar occur in many parts of the world as a coastal limestone whose formation is controlled by Quaternary climate change. Eolianite commonly has relatively low strength, high variability, and contains voids associated mainly with syngenetic karst. The presence of eolianite increases risks and costs to civil engineering construction. Seismic imaging of voids and weaker zones within soft-rock eolianites with P-waves is challenging as the material properties contrasts are often relatively small and highly variable.
Attenuation of free-surface multiples by up/down deconvolution for marine towed-streamer data
Authors: Majdański Mariusz , Kostov Clément , Kragh Ed , Moore Ian , Thompson Mark , Mispel Joachim
Published: January 2012

Free-surface-related multiples in marine seismic data are commonly attenuated using adaptive subtraction of the predicted multiple energy. An alternative method, based on deconvolution of the upgoing wavefield by the downgoing wavefield, was previously applied to ocean-bottom data. We apply the deconvolution method to towed-streamer data acquired in an over/under configuration. We also use direct arrival deconvolution that results in source wavelet designature only, as a benchmark to verify the full multiple deconvolution result. Detailed synthetic data analysis, including sensitivity tests, explains each data processing step and its effects on the final result. We then apply this verified preprocessing sequence to field data from the Kristin area of the North Sea, with a focus on the direct arrival prediction using the near-field hydrophone method. Prestack evaluation of the results shows that the method applied to the field data provides designature, source-side deghosting, and attenuation of multiples. We show comparable stacked results from our method and from 2D iterative surface-related multiple elimination. The workflow has the benefit that it does not require an adaptive subtraction step or iterative application. However, an accurate direct arrival prediction is essential for the successful application of the method. This prediction is obtained using near-field hydrophone measurements that can be recorded with some commercial acquisition systems.
Mineralocorticoid Receptor Overexpression Facilitates Differentiation and Promotes Survival of Embryonic Stem Cell-Derived Neurons
Authors: Munier Mathilde , Law Frédéric , Meduri Geri , Le Menuet Damien , Lombès Marc
Published: January 2012

Mineralocorticoid receptor (MR), highly expressed in the hippocampus, binds corticosteroid hormones and coordinately participates, with the glucocorticoid receptor, to the control of stress responses, memorization, and behavior. To investigate the impact of MR in neuronal survival, we generated murine embryonic stem (ES) cells that overexpress human MR (hMR) (P1-hMR) and are induced to differentiate into mature neurons. We showed that recombinant MR expression increased throughout differentiation and is 2-fold higher in P1-hMR ES-derived neurons compared with wild-type controls, whereas glucocorticoid receptor expression was unaffected. Although proliferation and early neuronal differentiation were comparable in P1-hMR and wild-type ES cells, MR overexpression was associated with higher late neuronal marker expression (microtubule-associated protein 2 and β-tubulin III). This was accompanied by a shift towards neuron survival with an increased ratio of anti- vs. proapoptotic molecules and 50% decreased caspase 3 activity. Knocking down MR overexpression by small interfering RNA drastically reversed neuroprotective effects with reduced Bcl2/Bax ratio and decreased microtubule-associated protein 2 expression. P1-hMR neurons were protected against oxidative stress-induced apoptosis through reduced caspase 3 activation and drastically increased Bcl2/Bax ratio and β-tubulin III expression. We demonstrated the involvement of MR in neuronal differentiation and survival and identify MR as an important neuroprotective mediator opening potential pharmacological strategies.
Activation of Latent Human GDF9 by a Single Residue Change (Gly391Arg) in the Mature Domain
Authors: Simpson Courtney M. , Stanton Peter G. , Walton Kelly L. , Chan Karen L. , Ritter Lesley J. , Gilchrist Robert B. , Harrison Craig A.
Published: January 2012

Growth differentiation factor 9 (GDF9) controls granulosa cell growth and differentiation during early ovarian folliculogenesis and regulates cumulus cell function and ovulation rate in the later stages of this process. Similar to other TGF-β superfamily ligands, GDF9 is secreted from the oocyte in a noncovalent complex with its prodomain. In this study, we show that prodomain interactions differentially regulate the activity of GDF9 across species, such that murine (m) GDF9 is secreted in an active form, whereas human (h) GDF9 is latent. To understand this distinction, we used site-directed mutagenesis to introduce nonconserved mGDF9 residues into the pro- and mature domains of hGDF9. Activity-based screens of the resultant mutants indicated that a single mature domain residue (Gly391) confers latency to hGDF9. Gly391 forms part of the type I receptor binding site on hGDF9, and this residue is present in all species except mouse, rat, hamster, galago, and possum, in which it is substituted with an arginine. In an adrenocortical cell luciferase assay, hGDF9 (Gly391Arg) had similar activity to mGDF9 (EC50 55 ng/ml vs. 28 ng/ml, respectively), whereas wild-type hGDF9 was inactive. hGDF9 (Gly391Arg) was also a potent stimulator of murine granulosa cell proliferation (EC50 52 ng/ml). An arginine at position 391 increases the affinity of GDF9 for its signaling receptors, enabling it to be secreted in an active form. This important species difference in the activation status of GDF9 may contribute to the variation observed in follicular development, ovulation rate, and fecundity between mammals.
Lipocalin 2 Deficiency Alters Estradiol Production and Estrogen Receptor Signaling in Female Mice
Authors: Guo Hong , Zhang Yuanyuan , Brockman David A. , Hahn Wendy , Bernlohr David A. , Chen Xiaoli
Published: January 2012

We have previously characterized lipocalin 2 (Lcn2) as a new adipokine having a critical role in energy and lipid metabolism in male mice. Previous studies by others have suggested that Lcn2 is a putative target gene of estrogens. In this study, we reported the effect of Lcn2 deficiency on estradiol biosynthesis and estrogen receptor signaling in female Lcn2-deficient (Lcn2−/−) mice. We found that Lcn2 expression in white adipose tissue is gender, depot, and age dependent. In female mice, Lcn2 is predominantly expressed in inguinal adipose tissue but at relatively very low levels in perigonadal depot and ovary. After 22 wk of high-fat diet (HFD) feeding or at old age, Lcn2−/− female mice had significantly reduced levels of serum 17β-estradiol and down-regulated expression of estrogen receptor α in multiple metabolic tissues. Consistently, the expression of estrogen-regulated genes involved in cholesterol homeostasis, such as liver X receptor β and low-density lipoprotein receptor was also down-regulated in the adipose tissue of Lcn2−/− mice. These changes were in line with the development of atherogenic dyslipidemia in response to HFD feeding; female Lcn2−/− mice had significantly elevated levels of total cholesterol and low-density lipoprotein cholesterol, whereas reduced high-density lipoprotein cholesterol levels compared with wild-type female mice. Interestingly, when compared with wild-type controls, HFD-fed female Lcn2−/− mice had significantly reduced expression levels of aromatase, a key enzyme regulating estradiol biosynthesis, in adipose tissue. Moreover, Lcn2 deficiency markedly blunted age-related increase in adipose aromatase expression but had no significant impact on age-related reduction in ovarian aromatase expression. Our findings suggest that Lcn2 has a tissue-specific role in adipose estradiol biosynthesis, which may link Lcn2 to obesity- and age-related estradiol production and metabolic complications in females.
WARBURG INSTITUTE ARCHIVE, GENERAL CORRESPONDENCE
Authors: Sears Elizabeth
Published: January 2012

Aby Warburg's Nachlass, the heart of the Warburg Institute Archive, is complemented by other large holdings which are no less remarkable. Quietly accumulating over the decades, still only provisionally cataloged, the vast corpus of letters filed as “General Correspondence” reveals itself to be a spectacularly rich resource for twentieth-century cultural and intellectual history. The secretariat was efficient: most everything was kept, letters received as well as copies of letters sent, meaning that the visitor to Woburn Square can sit in a single archive, read both sides of exchanges, and follow conversations over years — a rare circumstance. The academic staff maintained contact with an impressively large number of internationally active scholars, working in many fields, and the letters are characteristically substantive. In this article, the author indicates how a book she is presently writing, Warburg Circles, 1929 – 1964, has been shaped by these archival holdings. She offers a brief history of the consolidated archive now located on the fourth floor of the Warburg Institute, a story that throws light on recent scholarly trends; and she gives examples of the sorts of historical insight that may be gained from this corpus of correspondence.
WARBURG'S HAUNTED HOUSE
Authors: Didi-Huberman Georges
Published: January 2012

This article deals with the genesis of the Bilderatlas Mnemosyne, composed by Aby Warburg between 1927 and 1929 as a response to the Great War. His reaction to the war was both pathetic (even pathological) and epistemic (which is to say, methodological). If the history of culture amounted to a great psychomachia of the astra (concepts) and the monstra (chaos), as Warburg said, the war was for him a direct test of his theory (or Kulturwissenschaft). It should be no surprise, then, that between 1914 and 1918 he should assemble a large iconographic collection of materials from and about the war. This essay compares that collection and its theoretical foundations with similar projects of Warburg's contemporaries in France and Germany (notably those of the historians Lucien Febvre and Marc Bloch).
DROMENON
Authors: Wood Christopher S.
Published: January 2012

“Dromenon” was and is the rubric governing the fourth and final floor of Aby Warburg's Library. The word means “the thing done,” “the action,” and in the context of the Greek Mysteries referred to rites, as opposed to words and images. In the Warburg Library in London, dromenon covers law, social institutions, folklore, and customs, among which Warburg located politics. This essay is in large part a reflection on what Warburg understood by politics and its inherent conflict with libraries. For Warburg, both politics and libraries were ways of managing time; and the basic irony underscored in this article is that academic politics in the UK is now threatening the Warburg Library's continued existence.
THE LAW OF THE GOOD NEIGHBOR
Authors: Steinberg Michael P.
Published: January 2012

This essay portrays the “law of the good neighbor” as the principle of the Warburg Library's collections — as the argument for their expansion and coherence, as well as the principle governing the scholarly practice inspired by the Warburg Institute and “Warburg school” of cultural analysis. The essay includes a tribute to Anne Marie Meyer (1919 – 2004), Warburg scholar and long-time affiliate of the Institute, with special emphasis on the question that she uniquely raised: “Exactly what was the relation between [Aby] Warburg's research on paganism in the Renaissance and his meditations and fears about Judaism (and Jews)?”
THE LONGEST WAY AROUND IS THE SHORTEST WAY HOME
Authors: Crossley Paul
Published: January 2012

This article traces the roundabout journey of an architectural historian from Cambridge to the Warburg Institute Library, via Cracow, Princeton, and Manchester. The author's early research, into German and Central European architecture, had little to do with Warburgian interests, but in his studies in Cracow he became aware of the importance of architectural symbolism, via the friendship of his Cracow tutor, Lech Kalinowski, with Erwin Panofsky. As a corrective to Panofsky's idealist notion of the architectural symbol, the author was introduced to Richard Krautheimer's theory of the “copy,” first published in the Journal of the Warburg and Courtauld Institutes for 1942. It was this Warburgian model that launched the author's publications on the architectural symbolism of the Middle Ages. He writes that ending his journey as one of the editors of the Warburg and Courtauld Journal left him feeling that he had (in some sense) come home.
The Bond Premium in a DSGE Model with Long-Run Real and Nominal Risks
Authors: Rudebusch Glenn D , Swanson Eric T
Published: January 2012

The term premium in standard macroeconomic DSGE models is far too small and stable relative to the data—an example of the “bond premium puzzle.” However, in endowment economy models, researchers have generated reasonable term premiums by assuming investors have recursive Epstein-Zin preferences and face long-run economic risks. We show that introducing Epstein-Zin preferences into a canonical DSGE model can also produce a large and variable term premium without compromising the model's ability to fit key macroeconomic variables. Long-run nominal risks further improve the model's empirical fit, but do not substantially reduce the need for high risk aversion. (JEL E13, E31, E43, E44)
Tranching, CDS, and Asset Prices: How Financial Innovation Can Cause Bubbles and Crashes
Authors: Fostel Ana , Geanakoplos John
Published: January 2012

We show how the timing of financial innovation might have contributed to the mortgage bubble and then to the crash of 2007–2009. We show why tranching and leverage first raised asset prices and why CDS lowered them afterward. This may seem puzzling, since it implies that creating a derivative tranche in the securitization whose payoffs are identical to the CDS will raise the underlying asset price, while the CDS outside the securitization lowers it. The resolution of the puzzle is that the CDS lowers the value of the underlying asset since it is equivalent to tranching cash. (JEL E32, E44, G01, G12, G13, G21).
Terminology for biorelated polymers and applications (IUPAC
Recommendations 2012)
Authors: Vert Michel , Doi Yoshiharu , Hellwich Karl-Heinz , Hess Michael , Hodge Philip , Kubisa Przemyslaw , Rinaudo Marguerite , Schué François
Published: January 2012

Like most of the materials used by humans, polymeric materials are proposed in
the literature and occasionally exploited clinically, as such, as devices or as
part of devices, by surgeons, dentists, and pharmacists to treat traumata and
diseases. Applications have in common the fact that polymers function in contact
with animal and human cells, tissues, and/or organs. More recently, people have
realized that polymers that are used as plastics in packaging, as colloidal
suspension in paints, and under many other forms in the environment, are also in
contact with living systems and raise problems related to sustainability,
delivery of chemicals or pollutants, and elimination of wastes. These problems
are basically comparable to those found in therapy. Last but not least,
biotechnology and renewable resources are regarded as attractive sources of
polymers. In all cases, water, ions, biopolymers, cells, and tissues are
involved. Polymer scientists, therapists, biologists, and ecologists should thus
use the same terminology to reflect similar properties, phenomena, and
mechanisms. Of particular interest is the domain of the so-called “degradable or
biodegradable polymers” that are aimed at providing materials with specific
time-limited applications in medicine and in the environment where the respect
of living systems, the elimination, and/or the bio-recycling are mandatory, at
least ideally.
Subplate Neurons Promote Spindle Bursts and Thalamocortical Patterning in the Neonatal Rat Somatosensory Cortex
Authors: Tolner Else A. , Sheikh Aminah , Yukin Alexey Y. , Kaila Kai , Kanold Patrick O.
Published: January 2012

Patterned neuronal activity such as spindle bursts in the neonatal cortex is likely to promote the maturation of cortical synapses and neuronal circuits. Previous work on cats has shown that removal of subplate neurons, a transient neuronal population in the immature cortex, prevents the functional maturation of thalamocortical and intracortical connectivity. Here we studied the effect of subplate removal in the neonatal rat primary somatosensory cortex (S1). Using intracortical EEG we show that after selective removal of subplate neurons in the limb region of S1, endogenous and sensory evoked spindle burst activity is largely abolished. Consistent with the reducedin vivoactivity in the S1 limb region, we find byin vitrorecordings that thalamocortical inputs to layer 4 neurons are weak. In addition, we find that removal of subplate neurons in the S1 barrel region prevents the development of the characteristic histological barrel-like appearance. Thus, subplate neurons are crucially involved in the generation of particular types of early network activity in the neonatal cortex, which are an important feature of cortical development. The altered EEG pattern following subplate damage could be applicable in the neurological assessment of human neonates.
Adaptation of Binaural Processing in the Adult Brainstem Induced by Ambient Noise
Authors: Siveke Ida , Leibold Christian , Schiller Evelyn , Grothe Benedikt
Published: January 2012

Interaural differences in stimulus intensity and timing are major cues for sound localization. In mammals, these cues are first processed in the lateral and medial superior olive by interaction of excitatory and inhibitory synaptic inputs from ipsi- and contralateral cochlear nucleus neurons. To preserve sound localization acuity following changes in the acoustic environment, the processing of these binaural cues needs neuronal adaptation. Recent studies have shown that binaural sensitivity adapts to stimulation history within milliseconds, but the actual extent of binaural adaptation is unknown. In the current study, we investigated long-term effects on binaural sensitivity using extracellularin vivorecordings from single neurons in the dorsal nucleus of the lateral lemniscus that inherit their binaural properties directly from the lateral and medial superior olives. In contrast to most previous studies, we used a noninvasive approach to influence this processing. Adult gerbils were exposed for 2 weeks to moderate noise with no stable binaural cue. We found monaural response properties to be unaffected by this measure. However, neuronal sensitivity to binaural cues was reversibly altered for a few days. Computational models of sensitivity to interaural time and level differences suggest that upregulation of inhibition in the superior olivary complex can explain the electrophysiological data.
Tune It Down to Live It Up? Rapid, Nongenomic Effects of Cortisol on the Human Brain
Authors: Strelzyk Florian , Hermes Michael , Naumann Ewald , Oitzl Melly , Walter Christoph , Busch Hans-Peter , Richter Steffen , Schächinger Hartmut
Published: January 2012

The stress hormone cortisol acts on the brain, supporting adaptation and time-adjusted coping processes. Whereas previous research has focused on slow emerging, genomic effects of cortisol, we addressed the rapid, nongenomic cortisol effects onin vivoneuronal activity in humans. Three independent placebo-controlled studies in healthy men were conducted. We observed changes in CNS activity within 15 min after intravenous administration of a physiological dose of 4 mg of cortisol (hydrocortisone). Two of the studies demonstrated a rapid bilateral thalamic perfusion decrement using continuous arterial spin labeling. The third study revealed rapid, cortisol-induced changes in global signal strength and map dissimilarity of the electroencephalogram. Our data demonstrate that a physiological concentration of cortisol profoundly affects the functioning and perfusion of the human brainin vivovia a rapid, nongenomic mechanism. The changes in neuronal functioning suggest that cortisol acts on the thalamic relay of background as well as on task-specific sensory information, allowing focus and facilitation of adaptation to challenges.
RNA Binding Proteins Accumulate at the Postsynaptic Density with Synaptic Activity
Authors: Zhang Guoan , Neubert Thomas A. , Jordan Bryen A.
Published: January 2012

Neuronal activity elicits changes in synaptic composition that play an important role in experience-dependent plasticity (Choquet and Triller, 2003; Lisman and Raghavachari, 2006; Bourne and Harris, 2008; Holtmaat and Svoboda, 2009). We used a modified version of stable isotope labeling by amino acids in cell culture to identify activity-dependent modifications in the composition of postsynaptic densities (PSDs) isolated from rat primary neuronal cultures. We found that synaptic activity altered ∼2% of the PSD proteome, which included an increase in diverse RNA binding proteins (RNABPs). Indeed, 12 of the 37 identified proteins whose levels changed with synaptic activity were RNABPs and included the heterogeneous nuclear ribonucleoproteins (hnRNPs) G, A2/B1, M, and D. Knockdown of hnRNPs M and G using shRNAs resulted in altered numbers of dendritic spines, suggesting a crucial role for these proteins in spine density. Synaptic activity also resulted in a concomitant increase in dendritic and synaptic poly(A) mRNA. However, this increase was not affected by knockdown of hnRNPs M or G. Our results suggest that hnRNP proteins regulate dendritic spine density and may play a role in synaptodendritic mRNA metabolism.
Subsynaptic AMPA Receptor Distribution Is Acutely Regulated by Actin-Driven Reorganization of the Postsynaptic Density
Authors: Kerr Justin M. , Blanpied Thomas A.
Published: January 2012

AMPA receptors (AMPARs) mediate synaptic transmission and plasticity during learning, development, and disease. Mechanisms determining subsynaptic receptor position are poorly understood but are key determinants of quantal size. We used a series of live-cell, high-resolution imaging approaches to measure protein organization within single postsynaptic densities in rat hippocampal neurons. By photobleaching receptors in synapse subdomains, we found that most AMPARs do not freely diffuse within the synapse, indicating they are embedded in a matrix that determines their subsynaptic position. However, time lapse analysis revealed that synaptic AMPARs are continuously repositioned in concert with plasticity of this scaffold matrix rather than simply by free diffusion. Using a fluorescence correlation analysis, we found that across the lateral extent of single PSDs, component proteins were differentially distributed, and this distribution was continually adjusted by actin treadmilling. The C-terminal PDZ ligand of GluA1 did not regulate its mobility or distribution in the synapse. However, glutamate receptor activation promoted subsynaptic mobility. Strikingly, subsynaptic immobility of both AMPARs and scaffold molecules remained essentially intact even after loss of actin filaments. We conclude that receptors are actively repositioned at the synapse by treadmilling of the actin cytoskeleton, an influence which is transmitted only indirectly to receptors via the pliable and surprisingly dynamic internal structure of the PSD.
Neural Correlation Is Stimulus Modulated by Feedforward Inhibitory Circuitry
Authors: Middleton Jason W. , Omar Cyrus , Doiron Brent , Simons Daniel J.
Published: January 2012

Correlated variability of neural spiking activity has important consequences for signal processing. How incoming sensory signals shape correlations of population responses remains unclear. Cross-correlations between spiking of different neurons may be particularly consequential in sparsely firing neural populations such as those found in layer 2/3 of sensory cortex. In rat whisker barrel cortex, we found that pairs of excitatory layer 2/3 neurons exhibit similarly low levels of spike count correlation during both spontaneous and sensory-evoked states. The spontaneous activity of excitatory–inhibitory neuron pairs is positively correlated, while sensory stimuli actively decorrelate joint responses. Computational modeling shows how threshold nonlinearities and local inhibition form the basis of a general decorrelating mechanism. We show that inhibitory population activity maintains low correlations in excitatory populations, especially during periods of sensory-evoked coactivation. The role of feedforward inhibition has been previously described in the context of trial-averaged phenomena. Our findings reveal a novel role for inhibition to shape correlations of neural variability and thereby prevent excessive correlations in the face of feedforward sensory-evoked activation.
Action Reprogramming in Parkinson's Disease: Response to Prediction Error Is Modulated by Levels of Dopamine
Authors: Galea Joseph M. , Bestmann Sven , Beigi Mazda , Jahanshahi Marjan , Rothwell John C.
Published: January 2012

Humans are able to use knowledge of previous events to estimate the probability of future actions. Consequently, an unexpected event will elicit a prediction error as the prepared action has to be replaced by an unprepared option in a process known as “action reprogramming” (AR). Here we show that people with Parkinson's disease (PD) have a dopamine-sensitive deficit in AR that is proportional to the size of the prediction error. Participants performed a probabilistic reaction time (RT) task in the context of either a predictable or unpredictable environment. For an overall predictable sequence, PD patients, on and off dopamine medication, and healthy controls showed similar improvements in RT. However, in the context of a generally predictable sequence, PD patients off medication were impaired in reacting to unexpected events that elicit large prediction errors and require AR. Critically, this deficit in AR was modulated by the prediction error associated with the upcoming event. The prolongation of RT was not observed during an overall unpredictable sequence, in which relatively unexpected events evoke little prediction error and the requirement for AR should be minimal, given the context. The data are compatible with recent theoretical accounts suggesting that levels of dopamine encode the reliability, i.e., precision, of sensory information. In this scheme, PD patients off medication have low dopamine levels and may therefore be less confident about incoming sensory information and more reliant on top-down predictions. Consequently, when these internal predictions are incorrect, PD patients take longer to respond appropriately to unexpected sensory information.
Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation
Authors: Fleuriet Jérome , Goffart Laurent
Published: January 2012

Animals can make saccadic eye movements to intercept a moving object at the right place and time. Such interceptive saccades indicate that, despite variable sensorimotor delays, the brain is able to estimate the current spatiotemporal (hic et nunc) coordinates of a target at saccade end. The present work further tests the robustness of this estimate in the monkey when a change in eye position and a delay are experimentally added before the onset of the saccade and in the absence of visual feedback. These perturbations are induced by brief microstimulation in the deep superior colliculus (dSC). When the microstimulation moves the eyes in the direction opposite to the target motion, a correction saccade brings gaze back on the target path or very near. When it moves the eye in the same direction, the performance is more variable and depends on the stimulated sites. Saccades fall ahead of the target with an error that increases when the stimulation is applied more caudally in the dSC. The numerous cases of compensation indicate that the brain is able to maintain an accurate and robust estimate of the location of the moving target. The inaccuracies observed when stimulating the dSC that encodes the visual field traversed by the target indicate that dSC microstimulation can interfere with signals encoding the target motion path. The results are discussed within the framework of the dual-drive and the remapping hypotheses.
Matrix Metalloproteinase-7 Regulates Cleavage of Pro-Nerve Growth Factor and Is Neuroprotective following Kainic Acid-Induced Seizures
Authors: Le Audrey P. , Friedman Wilma J.
Published: January 2012

The neurotrophin nerve growth factor (NGF) regulates neuronal growth, differentiation, and survival during development. However, the precursor of NGF, proNGF, is a potent apoptotic ligand for the p75 neurotrophin receptor (p75NTR)–sortilin complex. The mechanisms that regulate cleavage of proNGF, therefore, are critical determinants of whether this factor promotes neuronal survival or death. In this study, we demonstrate that, following kainic acid-induced seizures, the proNGF processing enzyme matrix metalloproteinase 7 (MMP-7) and its inhibitor TIMP-1 (tissue inhibitor of matrix metalloproteinase 1) are regulated in a manner that prevents proneurotrophin cleavage and leads to increased proNGF in the extracellular milieu. Furthermore, we demonstrate bothin vitroandin vivothat exogenous MMP-7 enhances proNGF cleavage and provides neuroprotection following kainic acid treatment. These data demonstrate that increased extracellular proNGF levels following seizures are stabilized by altered MMP-7 enzymatic activity, leading to increased neuronal death via activation of p75NTR.
Vision Modulates Corticospinal Suppression in a Functionally Specific Manner during Movement of the Opposite Limb
Authors: Carson Richard G. , Ruddy Kathy L.
Published: January 2012

The effect of vision on the excitability of corticospinal projections to the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles of right human forearm was investigated before and during discrete movement of the opposite limb. An external force opposed the initial phase of the movement (wrist flexion) and assisted the reverse phase, so that recruitment of the wrist extensors was minimized. Three conditions were used as follows: viewing the inactive right limb (Vision), viewing the mirror image of the moving left limb (Mirror), and with vision of the right limb occluded (No Vision). Transcranial magnetic stimulation was delivered to the left motor cortex: before, at the onset of, or during the left limb movement to obtain motor evoked potentials (MEPs) in the muscles of the right forearm. At and following movement onset, MEPs obtained in the right FCR were smaller in the Vision condition than in the Mirror and No Vision conditions. A distinct pattern of variation was obtained for the ECR. In all conditions, MEPs in this muscle were elevated upon or following movement of the opposite limb. An additional analysis of ipsilateral silent periods indicated that interhemispheric inhibition plays a role in mediating these effects. Activity-dependent changes in corticospinal output to a resting limb during discrete actions of the opposite limb are thus directly contingent upon where one looks. Furthermore, the extent to which vision exerts an influence upon projections to specific muscles varies in accordance with the functional contribution of their homologs to the intended action.
Axonal Transport of Neurofilaments: A Single Population of Intermittently Moving Polymers
Authors: Li Yinyun , Jung Peter , Brown Anthony
Published: January 2012

Studies on mouse optic nerve have led to the controversial proposal that only a small proportion of neurofilaments are transported in axons and that the majority are deposited into a persistently stationary and extensively cross-linked cytoskeletal network that remains fixed in place for months without movement. We have used computational modeling to address this issue, taking advantage of the wealth of published kinetic and morphometric data available for neurofilaments in the mouse visual system. We show that the transport kinetics and distribution of neurofilaments in mouse optic nerve can all be explained fully by a “stop-and-go” model of neurofilament transport, in which axons contain a single population of neurofilaments that all move stochastically in a rapid, intermittent, and bidirectional manner. Importantly, we find that the transport kinetics are not consistent with deposition of neurofilaments into a persistently stationary phase, and that deposition models cannot account for the observed distribution of neurofilaments along mouse optic nerve axons. Finally, we show that the apparent existence of a stationary neurofilament network in mouse optic nerve is most likely an experimental artifact due to contamination of the neurofilament transport kinetics with cytosolic proteins that move at faster rates. Thus, there is no evidence for the deposition of axonally transported neurofilaments into a persistently stationary neurofilament network in optic nerve axons. We conclude that all of the neurofilaments move and that they do so with a single broad and continuous distribution of average rates that is dictated by their intermittent and stochastic motile behavior.
Membrane Phospholipid Asymmetry Counters the Adverse Effects of Sterol Overloading in the Golgi Membrane of Drosophila
Authors: Ma Zhiguo , Liu Zhonghua , Huang Xun
Published: January 2012

Cholesterol and phospholipids serve as structural and functional components of cellular membranes in all eukaryotes. Heterogeneity in cholesterol and phospholipid content both within and between different organelles is an important characteristic of eukaryotic membranes. How this heterogeneity is achieved and orchestrated to maintain proper cellular physiology remains poorly understood. We previously found that overexpression of the Drosophilaoxysterol-binding protein (OSBP) leads to sterol accumulation in the Golgi apparatus. Here, we show that Osbp overexpression in a set of neuroendocrine neurons compromises the function of the Golgi apparatus. It impairs trafficking of the neuropeptide bursicon and results in post-eclosion behavior defects characterized by unexpanded wings. We performed a genetic screen to identify modifiers that suppress the unexpanded wing phenotype. A putative phospholipid flippase-encoding gene, CG33298, was validated, suggesting that a membrane-asymmetry-directed mechanism balances cholesterol chaos within the Golgi membranes. Since the functional connection between cholesterol metabolism and the activity of phospholipid flippase has been implicated in studies in yeast and worms, our findings here support an evolutionarily conserved causal link between cholesterol homeostasis and phospholipid asymmetry that maintains normal cellular physiology.
A Novel Downstream Regulatory Element Cooperates with the Silencing Machinery to Repress EPA1 Expression in Candida glabrata
Authors: Gallegos-García Verónica , Pan Shih-Jung , Juárez-Cepeda Jacqueline , Ramírez-Zavaleta Candy Y , Martin-del-Campo Marcela Briones , Martínez-Jiménez Verónica , Castaño Irene , Cormack Brendan , De Las Peñas Alejandro
Published: January 2012

Candida glabrata, an opportunistic fungal pathogen, adheres to mammalian epithelial cells; adherence is mediated primarily by the Epa1 adhesin. EPA1 is a member of a large gene family of ∼23 paralogues, which encode putative adhesins. In this study, we address how EPA1 transcription is regulated. Our data show that EPA1 expression is subject to two distinct negative regulatory mechanisms. EPA1 transcription is repressed by subtelomeric silencing: the Sir complex (Sir2–Sir4), Rap1, Rif1, yKu70, and yKu80 are required for full repression. Activation of EPA1 occurs immediately after dilution of stationary phase (SP) cells into fresh media; however, transcription is rapidly repressed again, limiting expression to lag phase, just as the cells exit stationary phase. This repression following lag phase requires a cis-acting regulatory negative element (NE) located in the EPA1 3′-intergenic region and is independent of telomere proximity. Bioinformatic analysis shows that there are 10 copies of the NE-like sequence in the C. glabrata genome associated with other EPA genes as well as non-EPA genes.
Field Emission from Nanocrystalline Diamond/Carbon Nanowall Composite Films Deposited on Scratched Substrates
Authors: Cheng C.Y. , Nakashima M. , Teii K.
Published: January 2012

We report the deposition and field emission properties of nanostructured composites consisting of carbon nanowalls (CNWs) and nanocrystalline diamond films by introducing two kinds of substrate scratching pretreatment, i.e., undulation and ultrasonic vibration. With increasing duration of scratching pretreatment, the morphology of the deposits changes from simple CNWs to a film/CNW composite and lastly to CNWs on a film, and then the space between the walls is increased. The emission turn-on field is reduced from 2.1 V/μm for simple CNWs to around 1.2 V/μm for the composite films, accompanied by an increase in field enhancement factor. The results indicate that electric field screening between the walls is successfully suppressed by widening of the wall spacing.
Self-Patterning Rear Contact Schemes for Silicon Solar Cells
Authors: Lennon Alison , Lu Pei Hsuan , Lu Zhong , Wang Kai
Published: January 2012

Higher silicon solar efficiencies are possible if metal contact is made to the cell though openings in a well-passivated surface. Patterning for rear point-contact schemes has typically been achieved using deterministic patterning methods involving either the use of photolithography, laser or inkjet patterning. However, with these approaches it is difficult to achieve cost-effective, high-throughput and robust processing if very small and closely-spaced openings are required. In this paper we review recent progress in the use of self-patterning anodised aluminium oxide layers to both passivate and enable point metal contacts to the rear surface of silicon solar cells. We describe a wet chemical method for anodising aluminium layers thermally-evaporated on the rear surfaces of silicon solar cells, and demonstrate that the layers can result in excellent passivation of the underlying silicon and also enable metal contact to the solar cell. Additionally, we describe how patterning of either the anodic aluminium oxide layer or the source aluminium layer can result in patterns of metallic and dielectric regions on a surface, and how currently-available solar cell electroplating tools can be adapted to achieve anodisation of solar cells at commercial processing throughput rates.
Synthesis of ZnO Nanowires by Hydrothermal Technique for Integration Into Chalcopyrite Thin Films
Authors: Karaagac H. , Parlak M. , Islam M. Saif
Published: January 2012

Vertically oriented, highly dense ZnO nanowires (NWs) array was successfully grown on both glass and silicon substrates using hydrothermal technique. A systematic study was carried out to investigate the effects of growth parameters including growth time and thickness of ZnO seed layer on the quality of ZnO NWs in terms of their homogeneity and orientation in the vertical direction. The diameter as well as the length of grown ZnO NWs was found to be closely dependent on the thickness of the pre-coated ZnO seed layer. The structures of ZnO NWs and electron-beam evaporated AgGa0.5In0.5Se2 (AGIS) thin film have been characterized by X-ray diffraction measurements and optical properties were measured by transmission measurement. The optic band gap of AGIS thin film was found to be almost optimum (1.56 eV) to match the abundant part of solar cell spectrum. AGIS thin film was deposited on the synthesized ZnO NWs to form p-n heterojunction based inorganic solar cell, which exhibited photovoltaic behavior with a power conversion efficiency of 0.37 % under A.M (1.5) illumination.
Synthesis and Morphology Control of Carbon Nanotube/Polyaniline Composite for Chemical Sensing
Authors: Ding Mengning , Star Alexander
Published: January 2012

Composites of single-walled carbon nanotubes (SWNTs) and polyaniline (PAni) were synthesized using different approaches. SWNT/PAni nanocomposite with controlled core/shell morphology was achieved. Our chemical sensing tests showed that such core/shell morphology resulted in superior sensor performance, with an increased sensitivity to acetone vapors, and a reversible detection of hydrazine vapors. The reversible detection of parts-per-billion concentrations of hydrazine offers promise for a portable solid-state detector that has potential application in aerospace.
Vector Magneto-Optical Generalized Ellipsometry on Passivated Permalloy Slanted Columnar Thin Films
Authors: Schmidt Daniel , Briley Chad , Schubert Eva , Schubert Mathias
Published: January 2012

Vector magneto-optical generalized ellipsometry on passivated ferromagnetic permalloy slanted columnar thin films is reported. The nanostructured thin film was grown by electron-beam glancing angle deposition and subsequently coated with a thin Al2O3 layer by atomic layer deposition. Magneto-optical generalized ellipsometry data have been acquired while an external magnetic field H with constant amplitude was rotated with respect to the sample (spatial hysteresis loops). The magneto-optical coupling parameters, which are proportional to the sample magnetization M, reveal intriguing anisotropic magnetic behavior of the slanted columnar thin film. Three-dimensional graphs of the magneto-optical coupling parameters with respect to spatial hysteresis loops shown here are representative for the sample magnetization.
Synthesis of Si Nanowires by Electroless Etching Technique and Their Integration Into I-III-VI2 Thin Films For Solar Cells
Authors: Karaagac H. , Parlak M. , Saif Islam M.
Published: January 2012

Si nanowires (NWs) have been fabricated by Ag-assisted electroless etching technique using an HF/AgNO3 aqueous solution. Scanning electron microscopy (SEM) measurements have revealed that a highly dense array of Si NWs with length of ∼1.4 μm is formed over the surface of both n-type and p-type Si (100) substrates. Following the fabrication of Si NWs, electron-beam evaporated p-type AgGa0.5In0.5Se2 thin film was deposited on the n-type Si NWs to form p-n heterojunction solar cells. The fabricated solar cells yield a 5.50% power conversion efficiency under AM (1.5) illumination.
Amigos e vizinhos: uma rede social ativa para adultos e idosos hipertensos
Authors: Faquinello Paula , Marcon Sonia Silva
Published: January 2012

A rede familiar é fundamental na vida dos indivíduos, mas quando ela é ineficiente, os amigos desempenham um papel essencial no apoio físico e mental aos indivíduos. O objetivo foi compreender a atuação da rede representada pelos amigos e vizinhos de adultos e idosos hipertensos. O presente estudo é de abordagem qualitativa e foi realizado com 20 indivíduos de idade entre 50 e 80 anos, em Maringá - PR. Os resultados demonstraram que o tempo de moradia interfere no vínculo do hipertenso com seus vizinhos e apontaram os recursos e locais utilizados para o contato com os amigos. As amizades são importante fonte de apoio, podendo este vínculo ser mais forte que os laços consanguíneos. Ressaltamos a necessidade de os profissionais de saúde valorizarem as redes de amizade, pois isto serve como estratégia para uma assistência mais efetiva, contemplando o sujeito como um todo.
Reprocessamento de produtos médicos: uma proposta de modelo regulatório para hospitais brasileiros
Authors: Costa Eliana Auxiliadora Magalhães , Costa Ediná Alves , Graziano Kazuko Uchikawa , Padoveze Maria Clara
Published: January 2012

O reprocessamento de produtos médicos constitui um processo de extrema complexidade e importância, que requer tanto capacidade operacional para sua implantação, como qualificação técnica especializada dos profissionais envolvidos. As questões típicas do reprocessamento de produtos médicos envolvem aspectos técnicos, econômicos e regulatórios, tanto para os artigos ditos reusáveis quanto para aqueles considerados de uso único. Este estudo objetiva desenvolver um modelo regulatório para o reprocessamento de produtos médicos no Brasil, que atenda aos requisitos de qualidade e de segurança recomendados na literatura e que seja operacional nas condições dos serviços hospitalares brasileiros. A construção dessa proposta para o Sistema Nacional de Vigilância Sanitária baseou-se na técnica de Conferência de Consenso entre especialistas no tema. A partir das contribuições coletadas, foi elaborado um modelo regulatório para o reprocessamento de produtos médicos considerando as lacunas previamente identificadas no marco regulatório hoje vigente no Brasil.
Descrição de oferta e consumo dos psicofármacos em Centros de Atenção Psicossocial na Região Sul brasileira
Authors: Kantorski Luciane Prado , Jardim Vanda Maria da Rosa , Porto Adrize Rutz , Schek Gabriele , Cortes Jandro Moraes , Oliveira Michele Mandagará de
Published: January 2012

A descrição do consumo e da oferta de psicofármacos nos Centros de Atenção Psicossocial (CAPS) é relevante para a efetividade da assistência dos serviços de saúde mental. Objetivou-se descrever o consumo e a oferta destes em CAPS dos tipos I e II na Região Sul do Brasil. Trata-se de um estudo de delineamento transversal, no qual foram pesquisados, em maio e junho de 2006, aspectos estruturais desse serviço, através dos prontuários de 1.162 usuários e de questionários respondidos por 30 coordenadores dos CAPS em que esses usuários encontram-se em acompanhamento. Identificaram-se usuários predominantemente do sexo feminino, adultos de meia-idade, de baixa condição econômica, majoritariamente com o diagnóstico de depressão maior e o consumo de antidepressivos. Constatou-se também que pode haver carência de distribuição e fornecimento de psicofármacos na rede do SUS, o que prejudica a terapia medicamentosa desse serviço especializado de saúde mental, diante das condições socioeconômicas dos usuários.
Intervenções de enfermagem aos pacientes com acidente vascular encefálico: uma revisão integrativa de literatura
Authors: Cavalcante Tahissa Frota , Moreira Rafaella Pessoa , Guedes Nirla Gomes , Araujo Thelma Leite de , Lopes Marcos Venícios de Oliveira , Damasceno Marta Maria Coelho , Lima Francisca Elisângela Teixeira
Published: January 2012

O objetivo do estudo foi analisar o conhecimento sobre as intervenções de enfermagem aos pacientes hospitalizados por acidente vascular encefálico. Realizou-se uma revisão integrativa da literatura a partir de acesso on-line a cinco bases de dados, no mês de setembro de 2009. Utilizou-se os descritores Cuidados de Enfermagem e Acidente Cerebral Vascular nas línguas portuguesa, inglesa e espanhola. Foram encontrados 223 artigos e selecionados 12. Identificou-se nos artigos um maior número de intervenções de enfermagem assistenciais, seguidas das educacionais, gerenciais e de pesquisa. As do domínio assistencial estão mais relacionadas aos aspectos biológicos dos pacientes. Em relação às educativas, os artigos apontam o papel fundamental do enfermeiro, bem como dos familiares e dos cuidadores. A principal intervenção gerencial foi a coordenação dos cuidados. Quanto às intervenções de pesquisa foi identificada apenas uma descrita como o desenvolvimento e aprimoramento da prática de cuidados por meio de evidências clínicas.