bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural, optical and fluorescence properties of wet chemically synthesized ZnO:Pd2+ nanocrystals
Authors: Kaur Jasmeet , Kumar Praveen , Sathiaraj Thangaiah Stephen , Thangaraj Rengasamy
Published: January 2013

This paper presents the structural, optical and photoluminescence properties of wet chemically synthesized ZnO:Pd2+ colloidal nanocrystals characterised by X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopic techniques. Increase in lattice parameters from diffraction data indicates the incorporation of Pd2+ in the ZnO crystal lattice. A small amount of dopant favours the formation of stoichiometric ZnO nanoparticles; otherwise, non-stoichiometric nanocrystal formation was observed from the EDS data. The optical gap was found to decrease with the doping concentration, except for the small dopant level of 0.05% of Pd2+ where an increase in the optical gap was observed. Intensities of characteristic luminescence bands for pure ZnO nanocrystals (357, 387 and 420 nm) were found to decrease with the increasing Pd2+ concentration, and two new bands centred at 528 and 581 nm for 0.5% Pd2+ concentration were observed. These results have been explained on the basis of change in the oxygen vacancy-related defects and/or formation of new trap states which in turn affect the luminescence properties of ZnO:Pd2+ nanocrystals, which are important in the realisation of visible light-emitting solid-state devices.
Disease severity in K/BxN serum transfer-induced arthritis is not affected by IL-33 deficiency
Authors: Martin Praxedis , Talabot-Ayer Dominique , Seemayer Christian Alexander , Vigne Solenne , Lamacchia Céline , Rodriguez Emiliana , Finckh Axel , Smith Dirk E , Gabay Cem , Palmer Gaby
Published: January 2013

Introduction

Interleukin (IL)-33 is a cytokine of the IL-1 family, which signals through the ST2 receptor. Previous work suggested implication of the IL-33/ST2 axis in the pathogenesis of human and mouse arthritis. Here, we directly investigated the role of endogenous IL-33 in K/BxN serum transfer-induced arthritis by using IL-33 knockout (KO) mice.

Methods

Arthritis was induced by injection of complete K/BxN serum or purified IgG. Disease severity was monitored by clinical and histological scoring.

Results

K/BxN serum transfer induced pronounced arthritis with similar incidence and severity in IL-33 KO and wild-type (WT) mice. In contrast, disease development was significantly reduced in ST2 KO mice. IL-33 expression in synovial tissue was comparable in arthritic WT and ST2 KO mice, and absent in IL-33 KO mice. Transfer of purified arthritogenic IgG instead of complete K/BxN serum also resulted in similar arthritis severity in IL-33 KO and WT mice, excluding a contribution of IL-33 contained in the serum of donor mice to explain this result. We investigated additional potential confounding factors, including purity of genetic background, but the mechanisms underlying reduced arthritis in ST2 KO mice remained unclear.

Conclusions

The data obtained with IL-33 KO mice indicate that endogenous IL-33 is not required for the development of joint inflammation in K/BxN serum transfer-induced arthritis. On the contrary, arthritis severity was reduced in ST2 KO mice. This observation might relate to IL-33 independent effects of ST2, and/or reveal the existence of confounding variables affecting the severity of joint inflammation in these KO strains.
Circulating miR-375 as a Biomarker of β-Cell Death and Diabetes in Mice
Authors: Erener Suheda , Mojibian Majid , Fox Jessica K. , Denroche Heather C. , Kieffer Timothy J.
Published: January 2013

Type 1 diabetes is a progressive autoimmune disease that is largely silent in its initial stages. Yet, sensitive methods for detection of β-cell death and prediction and prevention of diabetes are lacking. Micro-RNAs (miRNAs) have been found at high concentrations in body fluids. Here in this study we sought to determine whether an islet enriched miRNA, miR-375, is a suitable blood marker to detect β-cell death and predict diabetes in mice. We measured miR-375 levels by quantitative RT-PCR in plasma samples of streptozotocin (STZ)-treated C57BL/6 mice and nonobese diabetic (NOD) mice. We also measured miR-375 levels in media samples of cytokine- or STZ-treated islets in the presence or absence of cell-death inhibitors. High-dose STZ administration dramatically increased circulating miR-375 levels, prior to the onset of hyperglycemia. Similarly, in the NOD mouse model of autoimmune diabetes, circulating miR-375 levels were significantly increased 2 weeks before diabetes onset. Moreover, cytokine- and STZ-induced cell death in isolated mouse islets produced a striking increase in extracellular miR-375 levels, which was reduced by cell death inhibitors. These data suggest that circulating miR-375 can be used as a marker of β-cell death and potential predictor of diabetes.
Betaglycan Alters NFκB-TGFβ2 Cross Talk to Reduce Survival of Human Granulosa Tumor Cells
Authors: Bilandzic Maree , Chu Simon , Wang Yao , Tan Han L. , Fuller Peter J. , Findlay Jock K. , Stenvers Kaye L.
Published: January 2013

The molecular pathways controlling granulosa cell tumor (GCT) survival are poorly understood. In many cell types, nuclear factor-κB (NFκB) and TGFβ coordinately regulate cell survival to maintain tissue homeostasis. Because GCT cell lines exhibit constitutively activated NFκB, we hypothesized that NFκB blocks TGFβ-mediated cell death in GCT cells. To test this hypothesis, we used the human GCT cell line KGN, which exhibits loss of betaglycan, a TGFβ co-receptor. After inhibition of NFκB in KGN cells, re-expression of betaglycan resulted in a decrease in cell viability, which was further decreased by TGFβ2. Intriguingly, TGFβ2 increased NFκB reporter activity in control cells, but betaglycan expression suppressed both basal and TGFβ2-stimulated NFκB activity. Chemical inhibition of Mothers against decapentaplegic homolog 2/3 (SMAD2/3) signaling or SMAD2/3 gene silencing revealed that both SMADs contributed to cell survival. Furthermore, inhibiting NFκB activity resulted in a specific reduction in SMAD3 expression. Conversely, overexpression of SMAD3 increased basal NFκB activity and countered betaglycan-mediated suppression of NFκB activity. Finally, ERK1/2 activation emerged as the point of convergence of NFκB, SMAD3, and TGFβ2/betaglycan governance of GCT cell viability. Key findings in KGN cells were reproduced in a second GCT cell line, COV434. Collectively, our data establish that both SMAD2/3 and NFκB signaling pathways support GCT cell viability and suggest the existence of a positive feedback loop between NFκB and SMAD3 signaling in late-stage GCT. Furthermore, our data suggest that loss of betaglycan during tumor progression in GCT alters the functional outcomes generated by NFκB and TGFβ pathway cross talk.
PAK–PIX interactions regulate adhesion dynamics and membrane protrusion to control neurite outgrowth
Authors: Santiago-Medina Miguel , Gregus Kelly A. , Gomez Timothy M.
Published: January 2013

The roles of P21-activated kinase (PAK) in the regulation of axon outgrowth downstream of extracellular matrix (ECM) proteins are poorly understood. Here we show that PAK1–3 and PIX are expressed in the developing spinal cord and differentially localize to point contacts and filopodial tips within motile growth cones. Using a specific interfering peptide called PAK18, we found that axon outgrowth is robustly stimulated on laminin by partial inhibition of PAK–PIX interactions and PAK function, whereas complete inhibition of PAK function stalls axon outgrowth. Furthermore, modest inhibition of PAK–PIX stimulates the assembly and turnover of growth cone point contacts, whereas strong inhibition over-stabilizes adhesions. Point mutations within PAK confirm the importance of PIX binding. Together our data suggest that regulation of PAK–PIX interactions in growth cones controls neurite outgrowth by influencing the activity of several important mediators of actin filament polymerization and retrograde flow, as well as integrin-dependent adhesion to laminin.
Dinosaur lactation?
Authors: Else Paul L.
Published: January 2013

Lactation is a process associated with mammals, yet a number of birds feed their newly hatched young on secretions analogous to the milk of mammals. These secretions are produced from various sections (crop organ, oesophageal lining and proventriculus) of the upper digestive tract and possess similar levels of fat and protein, as well as added carotenoids, antibodies and, in the case of pigeons and doves, epidermal growth factor. Parental care in avian species has been proposed to originate from dinosaurs. This study examines the possibility that some dinosaurs used secretory feeding to increase the rate of growth of their young, estimated to be similar to that of present day birds and mammals. Dinosaur ‘lactation’ could also have facilitated immune responses as well as extending parental protection as a result of feeding newly hatched young in nest environments. While the arguments for dinosaur lactation are somewhat generic, a case study for lactation in herbivorous site-nesting dinosaurs is presented. It is proposes that secretory feeding could have been used to bridge the gap between hatching and establishment of the normal diet in some dinosaurs.
Shock avoidance by discrimination learning in the shore crab (Carcinus maenas) is consistent with a key criterion for pain
Authors: Magee Barry , Elwood Robert W.
Published: January 2013

Nociception allows for immediate reflex withdrawal whereas pain allows for longer-term protection via rapid learning. We examine here whether shore crabs placed within a brightly lit chamber learn to avoid one of two dark shelters when that shelter consistently results in shock. Crabs were randomly selected to receive shock or not prior to making their first choice and were tested again over 10 trials. Those that received shock in trial 2, irrespective of shock in trial 1, were more likely to switch shelter choice in the next trial and thus showed rapid discrimination. During trial 1, many crabs emerged from the shock shelter and an increasing proportion emerged in later trials, thus avoiding shock by entering a normally avoided light area. In a final test we switched distinctive visual stimuli positioned above each shelter and/or changed the orientation of the crab when placed in the chamber for the test. The visual stimuli had no effect on choice, but crabs with altered orientation now selected the shock shelter, indicating that they had discriminated between the two shelters on the basis of movement direction. These data, and those of other recent experiments, are consistent with key criteria for pain experience and are broadly similar to those from vertebrate studies.
Zebrafish larvae evade predators by sensing water flow
Authors: Stewart William J. , Cardenas Gilberto S. , McHenry Matthew J.
Published: January 2013

The ability of fish to evade predators is central to the ecology and evolution of a diversity of species. However, it is largely unclear how prey fish detect predators in order to initiate their escape. We tested whether larval zebrafish (Danio rerio) sense the flow created by adult predators of the same species. When placed together in a cylindrical arena, we found that larvae were able to escape 70% of predator strikes (mean escape probability Pescape=0.7, N=13). However, when we pharmacologically ablated the flow-sensitive lateral line system, larvae were rarely capable of escape (mean Pescape=0.05, N=11). In order to explore the rapid events that facilitate a successful escape, we recorded freely swimming predators and prey using a custom-built camera dolly. This device permitted two-dimensional camera motion to manually track prey and record their escape response with high temporal and spatial resolution. These recordings demonstrated that prey were more than 3 times more likely to evade a suction-feeding predator if they responded before (Pescape=0.53, N=43), rather than after (Pescape=0.15, N=13), a predator's mouth opened, which is a highly significant difference. Therefore, flow sensing plays an essential role in predator evasion by facilitating a response prior to a predator's strike.
Minke whales maximise energy storage on their feeding grounds
Authors: Christiansen Fredrik , Víkingsson Gísli A. , Rasmussen Marianne H. , Lusseau David
Published: January 2013

Seasonal trends in energy storage of the minke whale (Balaenoptera acutorostrata), a capital breeder, were investigated in Iceland, a North Atlantic feeding ground. The aim was to better understand the energy acquisition strategies of minke whales and the energetic costs that different reproductive classes face during the breeding season. We modelled total blubber volume, using blubber thickness and morphometric measurements of individual whales. Blubber volume was influenced by body length, and was higher for pregnant females than mature whales. Blubber volume increased linearly through the feeding season at the same rate for mature (mean ± s.e.m.=0.0028±0.00103 m3 day−1; N=61 male, 5 female) and pregnant whales (0.0024±0.00100 m3 day−1; N=49), suggesting that minke whales aim to maximise energy storage while on the feeding grounds. The total amount of blubber accumulated over the feeding season (0.51±0.119 m3 for mature and 0.43±0.112 m3 for pregnant whales), together with energy stored as muscle and intra-abdominal fats, constitutes the total amount of energy available for reproduction (fetus development and lactation) on the breeding grounds, as well as migration, daily field metabolic rates, growth and body maintenance. No seasonal variation was observed for immature whales (N=4 male, 12 female), suggesting that they are investing most of their excess energy into growth rather than reproduction, in order to reach the length of sexual maturity faster and start reproducing earlier. Our novel modelling approach provides insight into large whale bioenergetics and life history strategies, as well as the relationship between single-site measurement of blubber thickness and total blubber volume.
Adsorption of CO2/CH4 Mixtures in a Molecular Model of Activated Carbon through Monte Carlo Simulations
Authors: Albesa Alberto G. , Rafti Matías , Vicente José L. , Sánchez Hernán , Húmpola Pablo
Published: January 2013

In this article, a nanoporous carbon model based on units of polyaromatic molecules with different number of rings is described. The adsorption isotherms of pure CO2, CH4 and equimolar mixtures, and isosteric heat calculations on these models substrates were obtained by Monte Carlo simulations. The results were analyzed in the framework of dual process Langmuir model (DPL) and on the basis of ideal adsorption solution theory. We found that both methods predict the adsorption isotherms of mixtures based on pure components data with reasonable accuracy. It has been demonstrated that the isosteric heat and selectivity of a mixture are intimately related. The DPL model does not predict the correct numerical value of selectivities; however, it predicts the correct behaviour. This is very useful as a fast method to indicate the adsorption behaviour of mixtures.
Dye Ligand Epoxide Chitosan/Alginate: A Potential New Stationary Phase for Human IgG Purification
Authors: Gondim Diego R. , Lima Luana P. , de Souza Maria C. M. , Bresolin Igor T. L. , Adriano Wellington S. , Azevedo Diana C. S. , Silva Ivanildo J.
Published: January 2013

Cibacron Blue F3GA immobilized as ligand onto epoxide chitosan/alginate composite was prepared and evaluated for the purification of human immunoglobulin G (IgG) isolated from human serum by dye-ligand affinity chromatography. The effect of buffer pH on IgG adsorption, kinetic and isothern adsorption of high-purity IgG were studied by batch adsorption. The adsorption isotherm data were well fitted (using 25 mmol/L sodium phosphate buffer at pH 6.0) by the Langmuir–Freundlich model with a maximum adsorption capacity of 99 mg/g, apparent dissociation constant of 1.2 × 10−6 mol/L and n equal to 4.86. Fixed-bed experiments were performed using high-purity IgG, achieving a recovery rate of 53%. Human serum diluted ten times was also injected into the column. An enrichment of IgG in the elution fraction with traces of human serum albumin was observed. According to the study results, this material can be applied in the purification of human IgG under optimized conditions.
Effect of the Intra-Particle Diffusion and Porous Structure on Models for Adsorption and Storage of Methane onto Activated Carbons
Authors: Sales Deivson C. S. , Martins Rodrigo G. , Jaguaribe Emerson F. , Abreu Cesar A. M.
Published: January 2013

Activated carbons were produced by chemical activation with H3PO4 (CAQ1) and ZnCl2 (CAQ2), and used for the methane storage under compression and adsorption. Storage evaluations were performed in a semi-pilot unit where temperature and pressure evolutions were measured (charge pressure: 3.0 MPa). Textural characteristics, absolute densities and specific heats of the activated carbons were measured and related to the performance of the storage system. Mathematical models were developed to predict temperature and pressure evolutions during the gas loading. Our results showed that activated carbon CAQ1 had higher absolute density and lower specific heat than CAQ2. Models that consider the pore-size distribution were the most representative of experimental data for both activated carbons.
Enantioseparation of Secnidazole by High-Performance Liquid Chromatography Using Amylose-Based Stationary Phase
Authors: Nascimento Ana C. , Perna Rafael F. , Cremasco Marco A. , Santana Cesar C.
Published: January 2013

The secnidazole, a drug used in hepatic amebiasis, giardiasis and bacterial vaginosis, was enantioseparated on a semi-preparative scale by high performance liquid chromatography (HPLC), using chiral stationary phase (CSP) containing amylose tris (3, 5-dimethylphenyl) carbamate on silica gel (Chiralpak® AD). The experiments were carried out under normal phase conditions and the separation method exhibited very high selectivity and resolutions. The chromatographic parameters and the effects of column temperature on the retention time and selectivity were evaluated. Thermodynamic parameters were obtained from van't Hoff plots, and the elution order of the enantiomers was determined by circular dichorism. The enantiomers of secnidazole were separated under overloaded conditions with a good performance.
Gold–Ceria SBA-15-Supported Catalyst for CO Preferential Oxidation: Surface and Reactivity Studies
Authors: Reyes-Carmona Álvaro , Talon Aldo , Moretti Elisa , Lenarda Maurizio , Jiménez-López Antonio , Rodríguez-Castellón Enrique
Published: January 2013

In this article, the preparation and application of gold and cerium catalysts supported on zirconium-doped mesoporous silica SBA-15 was studied. These materials have been prepared by two different methods and characterized to investigate their textural properties, dispersion of the active phases and oxidation states. Both materials exhibit a marked catalytic activity. The size of the gold nanoparticles is directly related to the CO conversion rate and to the selectivity towards CO2 exhibiting a strong temperature dependence. An X-ray photoelectron spectroscopic study of the composition and chemical state of the nanoparticles indicates the presence of Au in a metallic state. Transmission electron microscopic micrographs indicate that the best catalyst shows a higher dispersion of Au in spite of its lower gold surface content.
Equilibrium and Thermodynamic Studies of Zinc Adsorption on Expanded Vermiculite
Authors: Nishikawa Emily , Neto Ambrósio F.A. , Vieira Melissa G.A.
Published: January 2013

Because of industrial growth, large amounts of effluents are generated, which need to be treated. Among the micropollutants usually present in industrial effluents, heavy metals are especially dangerous to aquatic environment because they are bioaccumulated along the food chain. This work aims to study the removal of zinc ions in aqueous solution by adsorbing them onto expanded vermiculite. In addition, equilibrium and thermodynamics studies were carried out to verify the spontaneity and the characteristics of the process. Langmuir, Freundlich and Dubinin–Radushkevich's models were applied to the data obtained from isotherms at temperatures of 273, 293, 313 and 333 K. Furthermore, experiments in static system were carried out to choose a suitable eluent to this process, to find the metal concentration and identify a method for effective recovery of the adsorbent. This adsorption process was found to be spontaneous, favourable, endothermic and physical. The best eluting agent was ethylenediaminetetraacetic acid (0.1 M); however, for cycle adsorption experiments the best agent was CaCl2 (0.1 M).
Adsorption of Bovine Serum and Bovine Haemoglobin onto Chitosan Film
Authors: Estevam L.S. , Debone H.S. , Yoshida C.M.P. , da Silva C.F.
Published: January 2013

Chitosan is a natural polymer derived from chitin, a polysaccharide abundant in nature. The application of chitosan as a dressing material for burns presents advantages such as bacteriostatic and fungistatic activity, low toxicity and biocompatibility. In this work, the barrier properties and mechanical strength of chitosan were evaluated for subsequent use as a dressing material. The films were evaluated in terms of their protein adsorption using bovine serum albumin and bovine haemoglobin as model proteins. The chitosan films presented physical properties suitable to be in wound dressings, such as resistance, flexibility in handling, absorptive capacity and water vapour permeation ratio. The results of infrared spectroscopy indicated the qualitative adsorption of proteins on the chitosan surface film.
Managing Licensing in a Market for Technology
Authors: Arora Ashish , Fosfuri Andrea , Rønde Thomas
Published: January 2013

Technology licensing is an important means for companies to extract more value from their intellectual assets. We build a model that helps understand how licensing activity should be organized within large corporations. More specifically, we compare decentralization—where the business unit using the technology makes licensing decisions—to centralized licensing. The business unit has superior information about licensing opportunities but may not have the appropriate incentives because its rewards depend on product market performance. If licensing is decentralized, the business unit forgoes valuable licensing opportunities because the rewards for licensing are (optimally) weaker than those for product market profits. This distortion is stronger when production-based incentives, especially private benefits, of business unit managers are more powerful, making centralization more attractive. Surprisingly, we find that interdependency across business units may result in more, not less, decentralization. Furthermore, even though centralization results in less information, centralized licensing deals are larger. Our model conforms to the existing evidence that reports heterogeneity across firms in both licensing propensity and organization of licensing.

This paper was accepted by Bruno Cassiman, business strategy.
Do Analysts Sacrifice Forecast Accuracy for Informativeness?
Authors: Louis Henock , Sun Amy X. , Urcan Oktay
Published: January 2013

Analysts deviate from management guidance to correct for perceived earnings management. Although the deviations reduce forecast accuracy, they improve forecast informativeness, bringing the forecasts closer to the unmanaged earnings and reducing accruals mispricing. An implicit assumption in the literature is that more accurate analyst forecasts (i.e., estimates that are closer to the reported earnings) are better for investors, and that analysts' objective is to forecast the reported (managed) earnings accurately. Our analysis suggests that this is not necessarily the case and that an inaccurate forecast can actually be more informative than an accurate one. Prior studies on analysts' deviations from management guidance focus on analysts' incentives to issue estimates that managers can beat. These studies implicitly assume that analysts side with management against the interests of their clients. Our analysis indicates that analysts could also deviate from management guidance to provide useful valuation information to their clients.

This paper was accepted by Mary Barth, accounting.
Direct Characterization of Motion-Dependent Parameters of Sperm in a Microfluidic Device: Proof of Principle
Authors: Chen Yu-An , Chen Ken-Chao , Tsai Vincent FS , Huang Zi-Wei , Hsieh Ju-Ton , Wo Andrew M
Published: January 2013

BACKGROUND

Semen analysis is essential for evaluating male infertility. Besides sperm concentration, other properties, such as motility and morphology, are critical indicators in assessing sperm quality. Nevertheless, rapid and complete assessment of these measures still presents considerable difficulty and involves a range of complex issues. Here we present a microfluidic device capable of quantifying a range of properties of human sperm via the resistive pulse technique (RPT).

METHODS

An aperture, designed as a long channel, was used to allow the quantification of various properties as sperm swam through.

RESULTS

The time trace of the voltage drop across the aperture during sperm passage contained a wealth of information: the sperm volume was presented by the amplitude of the induced pulse, the swim velocity was evaluated via the duration, and the beat frequency was calculated from the voltage undulation superposed on the pulse signal. The RPT measurement of swim velocity and beat frequency showed a correlation with the same observation in a microscope (R2 = 0.94 and 0.70, respectively).

CONCLUSIONS

The proposed proof of principle enables substantial quantification of the motion-dependent properties of sperm. Because this approach requires only a current/voltage source and data analysis, it is economically advantageous compared with optical methods for characterizing sperm motion. Furthermore, this approach may be used to characterize sperm morphology.
Layer III Neurons Control Synchronized Waves in the Immature Cerebral Cortex
Authors: Namiki Shigehiro , Norimoto Hiroaki , Kobayashi Chiaki , Nakatani Kei , Matsuki Norio , Ikegaya Yuji
Published: January 2013

Correlated spiking activity prevails in immature cortical networks and is believed to contribute to neuronal circuit maturation; however, its spatiotemporal organization is not fully understood. Using wide-field calcium imaging from acute whole-brain slices of rat pups on postnatal days 1–6, we found that correlated spikes were initiated in the anterior part of the lateral entorhinal cortex and propagated anteriorly to the frontal cortex and posteriorly to the medial entorhinal cortex, forming traveling waves that engaged almost the entire cortex. The waves were blocked by ionotropic glutamatergic receptor antagonists but not by GABAergic receptor antagonists. During wave events, glutamatergic and GABAergic synaptic inputs were balanced and induced UP state-like depolarization. Magnified monitoring with cellular resolution revealed that the layer III neurons were first activated when the waves were initiated. Consistent with this finding, layer III contained a larger number of neurons that were autonomously active, even under a blockade of synaptic transmission. During wave propagation, the layer III neurons constituted a leading front of the wave. The waves did not enter the parasubiculum; however, in some cases, they were reflected at the parasubicular border and propagated back in the opposite direction. During this reflection process, the layer III neurons in the medial entorhinal cortex maintained persistent activity. Thus, our data emphasize the role of layer III in early network behaviors and provide insight into the circuit mechanisms through which cerebral cortical networks maturate.
Synthetic Tau Fibrils Mediate Transmission of Neurofibrillary Tangles in a Transgenic Mouse Model of Alzheimer's-Like Tauopathy
Authors: Iba Michiyo , Guo Jing L. , McBride Jennifer D. , Zhang Bin , Trojanowski John Q. , Lee Virginia M.-Y.
Published: January 2013

Tauopathies, including Alzheimer's disease (AD) and frontotemporal lobar degeneration with tau pathologies, are neurodegenerative diseases characterized by neurofibrillary tangles (NFTs) comprising filamentous tau protein. Although emerging evidence suggests that tau pathology may be transmitted, we demonstrate here that synthetic tau fibrils are sufficient to transmit tau inclusions in a mouse model. Specifically, intracerebral inoculation of young PS19 mice overexpressing mutant human tau (P301S) with synthetic preformed fibrils (pffs) assembled from recombinant full-length tau or truncated tau containing four microtubule binding repeats resulted in rapid induction of NFT-like inclusions that propagated from injected sites to connected brain regions in a time-dependent manner. Interestingly, injection of tau pffs into either hippocampus or striatum together with overlaying cortex gave rise to distinct pattern of spreading. Moreover, unlike tau pathology that spontaneously develops in old PS19 mice, the pff-induced tau inclusions more closely resembled AD NFTs because they were Thioflavin S positive, acetylated, and more resistant to proteinase K digestion. Together, our study demonstrates that synthetic tau pffs alone are capable of inducing authentic NFT-like tau aggregates and initiating spreading of tau pathology in a tauopathy mouse model.
Reduced GABAAReceptor-Mediated Tonic Inhibition in Aged Rat Auditory Thalamus
Authors: Richardson Ben D. , Ling Lynne L. , Uteshev Victor V. , Caspary Donald M.
Published: January 2013

Age-related deficits in detecting and understanding speech, which can lead to social withdrawal and isolation, have been linked to changes in the central auditory system. Many of these central age-related changes involve altered mechanisms of inhibitory neurotransmission, essential for accurate and reliable auditory processing. In sensory thalamus, GABA mediates fast (phasic) inhibition via synaptic GABAAreceptors (GABAARs) and long-lasting (tonic) inhibition via high-affinity (extrasynaptic) GABAARs, which provide a majority of the overall inhibitory tone in sensory thalamus. Due to a delicate balance between excitation and inhibition, alteration of normal thalamic inhibitory function with age and a reduction of tonic GABAAR-mediated inhibition may disrupt normal adult auditory processing, sensory gating, thalamocortical rhythmicity, and slow-wave sleep. The present study examines age-related homeostatic plasticity of GABAAR function in auditory thalamus or the medial geniculate body (MGB). Using thalamic slices from young adult (3–8 months) and aged (28–32 months) rats, these studies found a 45.5% reduction in GABAAR density and a 50.4% reduction in GABAAR-mediated tonic whole cell Cl−currents in the aged MGB. Synaptic GABAAR-mediated inhibition appeared differentially affected in aged lemniscal and nonlemniscal MGB. Except for resting membrane potential, basic properties were unaltered with age, including neuronal Cl−homeostasis determined using the gramicidin perforated patch-clamp method. Results demonstrate selective significant age-dependent deficits in the tonic inhibitory tone within the MGB. These data suggest that selective GABAAR subtype agonists or modulators might be used to augment MGB inhibitory neurotransmission, improving speech understanding, sensory gating, and slow-wave sleep for a subset of elderly individuals.
Early Musical Training and White-Matter Plasticity in the Corpus Callosum: Evidence for a Sensitive Period
Authors: Steele Christopher J. , Bailey Jennifer A. , Zatorre Robert J. , Penhune Virginia B.
Published: January 2013

Training during a sensitive period in development may have greater effects on brain structure and behavior than training later in life. Musicians are an excellent model for investigating sensitive periods because training starts early and can be quantified. Previous studies suggested that early training might be related to greater amounts of white matter in the corpus callosum, but did not control for length of training or identify behavioral correlates of structural change. The current study compared white-matter organization using diffusion tensor imaging in early- and late-trained musicians matched for years of training and experience. We found that early-trained musicians had greater connectivity in the posterior midbody/isthmus of the corpus callosum and that fractional anisotropy in this region was related to age of onset of training and sensorimotor synchronization performance. We propose that training before the age of 7 years results in changes in white-matter connectivity that may serve as a scaffold upon which ongoing experience can build.
Distinct Pathways for Rule-Based Retrieval and Spatial Mapping of Memory Representations in Hippocampal Neurons
Authors: Navawongse Rapeechai , Eichenbaum Howard
Published: January 2013

Hippocampal neurons encode events within the context in which they occurred, a fundamental feature of episodic memory. Here we explored the sources of event and context information represented by hippocampal neurons during the retrieval of object associations in rats. Temporary inactivation of the medial prefrontal cortex differentially reduced the selectivity of rule-based object associations represented by hippocampal neuronal firing patterns but did not affect spatial firing patterns. In contrast, inactivation of the medial entorhinal cortex resulted in a pervasive reorganization of hippocampal mappings of spatial context and events. These results suggest distinct and cooperative prefrontal and medial temporal mechanisms in memory representation.
Supplementation with 0.1% and 2% vitamin e in diabetic rats: analysis of myenteric neurons immunostained for myosin-V and nNOS in the jejunum
Authors: Tronchini Eleandro Aparecido , Trevizan Aline Rosa , Tashima Cristiano Massao , Pereira Renata Virginia Ferreira , Zanoni Jacqueline Nelisis
Published: January 2013

CONTEXT: Diabetes mellitus is a disease characterized by hyperglycemia that, when allowed to progress long-term untreated, develops vascular and neurological complications, which are responsible for the development of alterations in the enteric nervous system in diabetic patients. In the gastrointestinal tract, diabetes mellitus promotes motor and sensory changes, and in the reflex function of this system, causing gastroparesis, diarrhea, constipation, megacolon, slow gastrointestinal transit, gastric stasis and dilation with decreased or increased peristaltic contractions. Several studies have shown that oxidative stress is the main responsible for the vascular and neurological complications affecting the enteric nervous system of diabetics. OBJECTIVE: The effects of 0.1% and 2% vitamin E on myosin-V- and nNOS-immunoreactive neurons in the jejunum of diabetic rats were investigated. METHODS: Thirty rats were divided into the groups: normoglycemic, normoglycemic treated with 0.1% vitamin E, normoglycemic treated with 2% vitamin E, diabetic, diabetic treated with 0.1% vitamin E, and diabetic treated with 2% vitamin E. The neuronal density and areas of neuron cell bodies were determined. RESULTS: Diabetes (diabetic group) significantly reduced the number of myosin-V-immunoreactive neurons compared with the normoglycemic group. The diabetic treated with 0.1% vitamin E and diabetic treated with 2% vitamin E groups did not exhibit a greater density than the D group (P>0.05). Nitrergic density did not change with diabetes (P>0.05). The areas of myosin-V- and nNOS-immunoreactive neurons significantly increased in the normoglycemic treated with 2% vitamin E and diabetic groups compared with the normoglycemic group. CONCLUSION: Supplementation with 2% vitamin E had a neurotrophic effect only in the area of myosin-V-immunoreactive neurons compared with the diabetic group.
Freshly isolated hepatocyte transplantation in acetaminophen-induced hepatotoxicity model in rats
Authors: Rodrigues Daniela , Silveira Themis Reverbel Da , Matte Ursula
Published: January 2013

CONTEXT: Hepatocyte transplantation is an attractive therapeutic modality for liver disease as an alternative for orthotopic liver transplantation. OBJECTIVE: The aim of the current study was to investigate the feasibility of freshly isolated rat hepatocyte transplantation in acetaminophen-induced hepatotoxicity model. METHODS: Hepatocytes were isolated from male Wistar rats and transplanted 24 hours after acetaminophen administration in female recipients. Female rats received either 1x10(7) hepatocytes or phosphate buffered saline through the portal vein or into the spleen and were sacrificed after 48 hours. RESULTS: Alanine aminotransferase levels measured within the experiment did not differ between groups at any time point. Molecular analysis and histology showed presence of hepatocytes in liver of transplanted animals injected either through portal vein or spleen. CONCLUSION: These data demonstrate the feasibility and efficacy of hepatocyte transplantation in the liver or spleen in a mild acetaminophen-induced hepatotoxicity model.
Desempenho agronômico de cultivares de café resistentes à ferrugem no estado de Minas Gerais, Brasil
Authors: Carvalho Alex Mendonça de , Mendes Antônio Nazareno Guimarães , Botelho Cesar Elias , Oliveira Antonio Carlos Baião de , Rezende Juliana Costa de , Rezende Ramiro Machado
Published: January 2013

Objetivou-se no trabalho avaliar o comportamento de 24 cultivares de cafeeiro, sendo 22 resistentes à ferrugem e duas testemunhas suscetíveis, em diferentes ambientes de Minas Gerais, a fim de contribuir para a recomendação técnica. Os experimentos foram instalados em quatro municípios (Lavras, Campos Altos, Patrocínio e Turmalina). O delineamento experimental utilizado foi o de blocos casualizados com três repetições, no espaçamento de 3,5x0,7 m e parcelas de dez plantas. As avaliações de produtividade, porcentagem de grãos classificados em peneira 16 acima e vigor vegetativo referem-se a quatro colheitas (2008 a 2012). Foram avaliadas, também, a adaptabilidade e estabilidade da produtividade das cultivares. As cultivares Sabiá Tardio, Pau Brasil MG1, Obatã IAC 1669-20, Catucaí Amarelo 24/137 e IPR 103 são promissoras para as referidas regiões cafeeiras. Essas cultivares aliam estabilidade e adaptabilidade independentemente do ambiente, com desempenho agronômico superior.
A Governança econômica global e os desafios do G-20 pós-crise financeira: análise das posições de Estados Unidos, China, Alemanha e Brasil
Authors: Ramos Leonardo , Vadell Javier , Saggioro Ana , Fernandes Márcia
Published: January 2013

A crise financeira de 2008 teve impactos significativos no capitalismo global, sendo um de seus reflexos na estrutura da governança global a constituição e evolução do G-20. Neste contexto, o objetivo do artigo é analisar tais mudanças e, em especial, as posições de quatro dos principais atores nas cúpulas do G-20, a saber: Estados Unidos, China, Alemanha e Brasil.
Chacal ou Cordeiro? O Brasil frente aos desafios e oportunidades do Sistema Internacional
Authors: Rodriguez Júlio César Cossio
Published: January 2013

Este artigo analisa as configurações da política externa brasileira pós-2002 para relacionar os ganhos e perdas com as mudanças estruturais do sistema internacional. O intuito e realizar um balanço das capacidades materiais do Brasil, assim como dos seus desafios e oportunidades, a partir das categorias propostas por Randall Schweller. Chacal ou Cordeiro? Como se comporta o Brasil num sistema internacional em transição e quais podem ser as consequências? Ou seja, atua como chacal na busca de ganhos relativos ao seguir o ator mais revisionista (China), e como cordeiro na associação direta com a potência unipolar.
Atratividade de genótipos de feijão-caupi para oviposição de Bemisia tabaci biótipo B
Authors: Cruz Patrícia Leite , Baldin Edson Luiz Lopes , Castro Maria de Jesus Passos de , Fanela Thiago Luis Martins , Silva Paulo Henrique Soares da
Published: January 2013

O objetivo deste trabalho foi avaliar a atratividade de genótipos de feijão-caupi para oviposição de Bemisia tabaci biótipo B e identificar possíveis fontes de resistência à mosca-branca. Foram avaliados 51 genótipos, com uso de testes de chance de escolha. Os genótipos foram divididos aleatoriamente em dois grupos, tendo-se utilizado o genótipo Canapu como testemunha sucetível. Os 14 genótipos mais promissores (sete de cada grupo) foram selecionados para a realização de ensaios complementares (com ou sem chance de escolha). No teste com chance de escolha, os genótipos BRS-Urubuquara, TVU-36, TE93-244-23 F-1, BR 17-Gurgueia, BRS-Marataoã, MNC99-541 F-21 e TE97-304 G-4 foram menos atrativos à mosca-branca. Os genótipos TE93-244-23 F-1 e TVU-36 apresentaram resistência pelo mecanismo de não preferência para ovoposição. No teste sem chance de escolha, apenas o genótipo TVU-36 apresentou resistência por esse mecanismo.
Fosfito de potássio no controle do míldio da videira e características físico-químicas de uvas Merlot
Authors: Pereira Vanessa Foresti , Resende Mário Lúcio Vilela de , Ribeiro Júnior Pedro Martins , Regina Murillo de Albuquerque , Mota Renata Vieira da , Vitorino Luiz Rodolpho Rodrigues
Published: January 2013

O objetivo deste trabalho foi avaliar o efeito de doses crescentes de duas formulações de fosfito de potássio, sobre a severidade do míldio da videira, produtividade e características físico-químicas de uvas Merlot. Foram avaliadas duas formulações de fosfito de potássio (Phi A e B), nas doses 0, 1,2, 2,5, 3,7 e 5,0 g L-1 de P2O5, comparadas com um fertilizante foliar e fungicidas, nas safras de 2009/2010 e 2010/2011. Observou-se efeito linear das doses de fosfito sobre a redução da severidade do míldio, nas duas safras. A maior dose de Phi A proporcionou controle médio de 60,5% e a de Phi B de 57,7%, semelhante ao controle pelos fungicidas (64,3%) e pelo fertilizante foliar (53,3%). Na primeira safra, Phi B proporcionou maior produtividade e, na segunda, não diferiu do tratamento com o fungicida. Os tratamentos somente produziram efeito sobre teor de sólidos solúveis, pH e acidez total titulável do mosto na segunda safra. Phi B e fungicidas proporcionaram os maiores teores de compostos fenólicos solúveis totais das cascas, porém, não produziram efeito sobre os teores de antocianinas. A aplicação de fosfito de potássio aumenta o teor de sólidos solúveis totais e o pH, reduz a acidez total titulável das bagas, não afeta o teor de antocianinas e é alternativa eficaz para o controle do míldio da videira, com resposta similar à proporcionada por fungicidas.
Perfilhamento como característica mitigadora dos prejuízos ocasionados ao milho pela desfolha do colmo principal
Authors: Sangoi Luís , Schmitt Amauri , Silva Paulo Regis Ferreira da , Vargas Vitor Paulo , Zoldan Sérgio Roberto , Viera Jefferson , Souza Clovis Arruda de , Picoli Junior Gilmar José , Bianchet Paula
Published: January 2013

O objetivo deste trabalho foi verificar se os perfilhos podem mitigar os prejuízos ocasionados pela desfolha do colmo principal em milho. Os experimentos foram implantados em Lages, SC, em 20/10/2006 e 31/10/2008. O delineamento experimental utilizado foi o de blocos ao acaso, com parcelas subdivididas. Na parcela principal, foram testados dois destinos dos perfilhos: manutenção até a colheita e remoção quando o colmo principal apresentava nove folhas expandidas (V9). Nas subparcelas, avaliaram-se quatro épocas de desfolha do colmo principal: V9, V15 (quinze folhas expandidas), VT (pendoamento) e folhas preservadas até a colheita. Avaliou-se o híbrido P30F53, à densidade de 55 mil plantas por hectare. Determinaram-se: a produtividade total, a do colmo principal e a dos perfilhos. As desfolhas realizadas em V15 e VT diminuíram a produtividade, em comparação ao tratamento sem desfolha, independentemente do destino dos perfilhos. Quando o milho foi desfolhado em V15 e VT, a produtividade total das parcelas em que os perfilhos foram mantidos foi maior do que daquelas em que eles foram removidos. Isto indica que os perfilhos foram benéficos ao colmo principal do milho, quando houve restrições à produção de carboidrato oriundas da perda de área foliar próximo do florescimento.
Simulación de los cambios de carbono orgánico del suelo en sistema de cultivo con higuerilla por el modelo RothC
Authors: Molina Lucila González , Moreno Pérez Esaú del C. , Krishnamurty Laksmi Reddiar , Pérez Aurelio Baéz , Miguel Acosta Mireles
Published: January 2013

El objetivo del presente trabajo fue la simulación de los cambios del carbono orgánico del suelo (COS), por el modelo RothC, en razón del cambio de uso de suelo del sistema tradicional - asociación maíz-calabaza (TMC) - a sistemas con higuerilla (Ricinus communis): multiestratos (MUL), callejones (CALL) y monocultivo de higuerilla (HIG). Las simulaciones del COS se hicieron para las profundidades de suelo 0-20 y 0-40 cm, para el periodo de 1980-2040, considerándose como línea base al sistema TMC. Las tasas de cambio de COS estimadas con el RothC, en ambas profundidades de suelo, estuvieron en 0,5-1,2, 0,4-0,8, 0,3-0,5 y 0,04-0,1 Mg ha-1 de C por año en los sistemas HIG, MUL, CALL y TMC, respectivamente, y fueron consistentes con las reportadas en la literatura. El desempeño del RothC tuvo 89% de eficiencia (EF), con R²=0,9, lo que muestra que este modelo puede usarse con información temporal del COS escasa, información de la historia de uso de suelo y mediciones de la entrada de residuos vegetales aéreos y subterráneos en el suelo.
Posiciones periféricas en la revitalización del Judaísmo Ortodoxo en Buenos Aires
Authors: Setton Damián
Published: January 2013

El trabajo analiza las diferentes formas en que actores sociales autodefinidos como judíos se relacionan con las instituciones del campo judaico. Enmarcado en el debate acerca de la revitalización de la ortodoxia, se propone como objetivo dar cuenta de cómo los actores sociales experimentan el espacio de lo judío. De este modo, toma en cuenta a una franja de individuos que se relacionan con la ortodoxia desde posiciones periféricas a las instituciones. Analizando las trayectorias de los actores, se observa que el proceso de revitalización de la ortodoxia puede ser analizado en términos de experiencias de descomunitarización.
O percurso de vida que faz o gênero: reflexões antropológicas a partir de etnografias desenvolvidas com pentecostais no Brasil e em Moçambique
Authors: Mafra Clara
Published: January 2013

Neste artigo eu retomo o debate em torno da "Batalha Espiritual" relacionando-a com a constituição de gênero entre os pentecostais. Apoiada em dados etnográficos, eu argumento que uma compreensão mais nuançada do dualismo pentecostal deve incluir, além de um processo de negociação na relação com a alteridade, a performance de uma relação com uma "fonte original" uma vez que, muito explicitamente, os pentecostais não identificam a si mesmos como "autores" da pessoa que constituem, mas como "testemunhas" da palavra bíblica e "imitadores" de Cristo.
Inscrição e circulação: novas visibilidades e configurações do espaço público em São Paulo
Authors: Caldeira Teresa Pires do Rio
Published: January 2013

Uma série de intervenções produzidas por homens jovens estão transformando os espaços públicos de São Paulo e rearticulando as profundas desigualdades sociais que sempre marcaram a cidade. O artigo analisa dois modos de intervenção: a produção de inscrições e o deslocamento pelo espaço urbano. A "produção de inscrições" refere-se à proliferação de grafites e pixações, ambos em estilos típicos de São Paulo. Já o deslocamento espacial alude às novas práticas de circulação pela cidade, como o motociclismo, o skate e o parkour. Essas intervenções garantem uma nova visibilidade a jovens vindos das periferias, desafiam noções prévias sobre o funcionamento dos espaços públicos, e revelam novas contradições da esfera pública democrática.
Bienais sem fronteiras?
Authors: Wu Chin-Tao
Published: January 2013

Terá o mundo das artes se tornado poroso, aberto a todos os artistas, independentemente de suas origens - mesmo se vierem de lugares que Paris ou Nova York consideram os mais marginais?