bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Accuracy of Fluid Models for Capacity Sizing in Queueing Systems with Impatient Customers
Authors: Bassamboo Achal , Randhawa Ramandeep S.
Published: August 2010

We consider queueing systems in which customers arrive according to a Poisson process and have exponentially distributed service requirements. The customers are impatient and may abandon the system while waiting for service after a generally distributed amount of time. The system incurs customer-related costs that consist of waiting and abandonment penalty costs. We study capacity sizing in such systems to minimize the sum of the long-term average customer-related costs and capacity costs. We use fluid models to derive prescriptions that are asymptotically optimal for large customer arrival rates. Although these prescriptions are easy to characterize, they depend intricately upon the distribution of the customers' time to abandon and may prescribe operating in a regime with offered load (the ratio of the arrival rate to the capacity) greater than 1. In such cases, we demonstrate that the fluid prescription is optimal up to O(1). That is, as the customer arrival rate increases, the optimality gap of the prescription remains bounded.
p62+ Hyaline Inclusions in Intrahepatic Cholangiocarcinoma Associated With Viral Hepatitis or Alcoholic Liver Disease
Authors: Aishima Shinichi , Fujita Nobuhiro , Mano Yohei , Iguchi Tomohiro , Taketomi Akinobu , Maehara Yoshihiko , Oda Yoshinao , Tsuneyoshi Masazumi
Published: August 2010

Mallory bodies (MBs) and hyaline globules (HGs) are recognized as hepatocellular cytoplasmic inclusions in liver diseases. We reviewed 123 intrahepatic cholangiocarcinomas (ICCs) and encountered 16 cases (13.0%) in which cancer cells had MB-type inclusions and/or HG-type inclusions, both of which are positive for p62 and ubiquitin. The HG type was present in all 16 cases, and 5 cases contained the MB type. Of 16 patients, 12 had chronic liver disease that was related to alcoholic abuse in 4, hepatitis B surface antigen–positive in 3, and hepatitis C virus antibody–positive in 8. Viral infection and liver cirrhosis were more common in ICCs with p62+ inclusions (P = .0004 and P = .0199, respectively). Of 16 ICCs, 15 with hyaline inclusions had a peripheral tumor location (P = .0052). On ultrastructural examination, the MB type had an electron-dense fibrillar appearance, while the HG type appeared as rounded masses of granular materials. Our results suggest that intracytoplasmic hyaline bodies occasionally can be found in cholangiocarcinoma with chronic liver disease related to viral hepatitis or alcoholic intake.
Improving Quality Management Systems of Laboratories in Developing Countries
Authors: Yao Katy , McKinney Barbara , Murphy Anna , Rotz Phil , Wafula Winnie , Sendagire Hakim , Okui Scolastica , Nkengasong John N.
Published: August 2010

The Strengthening Laboratory Management Toward Accreditation (SLMTA) program was developed to promote immediate, measurable improvement in laboratories of developing countries. The laboratory management framework, a tool that prescribes managerial job tasks, forms the basis of the hands-on, activity-based curriculum. SLMTA is implemented through multiple workshops with intervening site visits to support improvement projects. To evaluate the effectiveness of SLMTA, the laboratory accreditation checklist was developed and subsequently adopted by the World Health Organization Regional Office for Africa (WHO AFRO). The SLMTA program and the implementation model were validated through a pilot in Uganda. SLMTA yielded observable, measurable results in the laboratories and improved patient flow and turnaround time in a laboratory simulation. The laboratory staff members were empowered to improve their own laboratories by using existing resources, communicate with clinicians and hospital administrators, and advocate for system strengthening. The SLMTA program supports laboratories by improving management and building preparedness for accreditation.
Validation of Lamellar Body Counts Using Three Hematology Analyzers
Authors: Lockwood Christina M. , Crompton J. Chance , Riley Joan K. , Landeros Keith , Dietzen Dennis J. , Grenache David G. , Gronowski Ann M.
Published: August 2010

The lamellar body count (LBC) represents an alternative method to the TDx-FLM II (Abbott Laboratories, Abbott Park, IL), which is planned to be discontinued, for assessing fetal lung maturity. Our objective was to validate the LBC on 3 hematology analyzers (Coulter LH 750 and Coulter Ac·T diff2, Beckman Coulter, Brea, CA; and Sysmex XE-2100, Sysmex, Mundelein, IL) to serve as a template for other laboratories attempting to perform in-house validation.

Intra-assay and interassay coefficients of variation ranged from 1.7% to 21.8% and 1.9% to 7.1%, respectively, and all analyzers demonstrated excellent linearity. Whole blood and meconium were shown to interfere with LBCs, and specimens with these contaminants should be tested using phosphatidyl glycerol. With a TDx-FLM II cutoff of 55 mg/g or more and an LBC cutoff of 50,000/μL or more for maturity, concordance between the TDx-FLM II and the LBC on all instruments was poor (<80% in all cases). Concordance between hematology analyzers was excellent (≥94%). When laboratories are performing in-house validations, they should not correlate LBC with TDx-FLM II results without outcome data. Correlation with another validated LBC method is preferred.
White Americans' opposition to affirmative action: Group interest and the harm to beneficiaries objection
Authors: O'Brien Laurie T. , Garcia Donna. , Crandall Christian S. , Kordys Justin.
Published: August 2010

We focused on a powerful objection to affirmative action – that affirmative action harms its intended beneficiaries by undermining their self‐esteem. We tested whether White Americans would raise the harm to beneficiaries objection particularly when it is in their group interest. When led to believe that affirmative action harmed Whites, participants endorsed the harm to beneficiaries objection more than when led to believe that affirmative action did not harm Whites. Endorsement of a merit‐based objection to affirmative action did not differ as a function of the policy's impact on Whites. White Americans used a concern for the intended beneficiaries of affirmative action in a way that seems to further the interest of their own group.
Spectral Integration in Primary Auditory Cortex Attributable to Temporally Precise Convergence of Thalamocortical and Intracortical Input
Authors: Happel Max F. K. , Jeschke Marcus , Ohl Frank W.
Published: August 2010

Primary sensory cortex integrates sensory information from afferent feedforward thalamocortical projection systems and convergent intracortical microcircuits. Both input systems have been demonstrated to provide different aspects of sensory information. Here we have used high-density recordings of laminar current source density (CSD) distributions in primary auditory cortex of Mongolian gerbils in combination with pharmacological silencing of cortical activity and analysis of the residual CSD, to dissociate the feedforward thalamocortical contribution and the intracortical contribution to spectral integration. We found a temporally highly precise integration of both types of inputs when the stimulation frequency was in close spectral neighborhood of the best frequency of the measurement site, in which the overlap between both inputs is maximal. Local intracortical connections provide both directly feedforward excitatory and modulatory input from adjacent cortical sites, which determine how concurrent afferent inputs are integrated. Through separate excitatory horizontal projections, terminating in cortical layers II/III, information about stimulus energy in greater spectral distance is provided even over long cortical distances. These projections effectively broaden spectral tuning width. Based on these data, we suggest a mechanism of spectral integration in primary auditory cortex that is based on temporally precise interactions of afferent thalamocortical inputs and different short- and long-range intracortical networks. The proposed conceptual framework allows integration of different and partly controversial anatomical and physiological models of spectral integration in the literature.
Implicit Perceptual Anticipation Triggered by Statistical Learning
Authors: Turk-Browne Nicholas B. , Scholl Brian J. , Johnson Marcia K. , Chun Marvin M.
Published: August 2010

Our environments are highly regular in terms of when and where objects appear relative to each other. Statistical learning allows us to extract and represent these regularities, but how this knowledge is used by the brain during ongoing perception is unclear. We used rapid event-related fMRI to measure hemodynamic responses to individual visual images in a continuous stream that contained sequential contingencies. Sixteen human observers encountered these statistical regularities while performing an unrelated cognitive task, and were unaware of their existence. Nevertheless, the right anterior hippocampus showed greater hemodynamic responses to predictive stimuli, providing evidence for implicit anticipation as a consequence of unsupervised statistical learning. Hippocampal anticipation based on predictive stimuli correlated with subsequent processing of the predicted stimuli in occipital and parietal cortex, and anticipation in additional brain regions correlated with facilitated object recognition as reflected in behavioral priming. Additional analyses suggested that implicit perceptual anticipation does not contribute to explicit familiarity, but can result in predictive potentiation of category-selective ventral visual cortex. Overall, these findings show that future-oriented processing can arise incidentally during the perception of statistical regularities.
The Postsynaptic Adenomatous Polyposis Coli (APC) Multiprotein Complex Is Required for Localizing Neuroligin and Neurexin to Neuronal Nicotinic Synapsesin Vivo
Authors: Rosenberg Madelaine M. , Yang Fang , Mohn Jesse L. , Storer Elizabeth K. , Jacob Michele H.
Published: August 2010

Synaptic efficacy requires that presynaptic and postsynaptic specializations align precisely and mature coordinately. The underlying mechanisms are poorly understood, however. We propose that adenomatous polyposis coli protein (APC) is a key coordinator of presynaptic and postsynaptic maturation. APC organizes a multiprotein complex that directs nicotinic acetylcholine receptor (nAChR) localization at postsynaptic sites in avian ciliary ganglion neuronsin vivo. We hypothesize that the APC complex also provides retrograde signals that direct presynaptic active zones to develop in register with postsynaptic nAChR clusters. In our model, the APC complex provides retrograde signals via postsynaptic neuroligin that interacts extracellularly with presynaptic neurexin. S-SCAM (synaptic cell adhesion molecule) and PSD-93 (postsynaptic density-93) are scaffold proteins that bind to neuroligin. We identify S-SCAM as a novel component of neuronal nicotinic synapses. We show that S-SCAM, PSD-93, neuroligin and neurexin are enriched at α3*-nAChR synapses. PSD-93 and S-SCAM bind to APC and its binding partner β-catenin, respectively. Blockade of selected APC and β-catenin interactions,in vivo, leads to decreased postsynaptic accumulation of S-SCAM, but not PSD-93. Importantly, neuroligin synaptic clusters are also decreased. On the presynaptic side, there are decreases in neurexin and active zone proteins. Further, presynaptic terminals are less mature structurally and functionally. We define a novel neural role for APC by showing that the postsynaptic APC multiprotein complex is required for anchoring neuroligin and neurexin at neuronal synapsesin vivo. APC human gene mutations correlate with autism spectrum disorders, providing strong support for the importance of the association, demonstrated here, between APC, neuroligin and neurexin.
Physiological Activation of Synaptic Rac>PAK (p-21 Activated Kinase) Signaling Is Defective in a Mouse Model of Fragile X Syndrome
Authors: Chen Lulu Y. , Rex Christopher S. , Babayan Alex H. , Kramár Eniko A. , Lynch Gary , Gall Christine M. , Lauterborn Julie C.
Published: August 2010

The abnormal spine morphology found in fragile X syndrome (FXS) is suggestive of an error in the signaling cascades that organize the actin cytoskeleton. We report here that physiological activation of the small GTPase Rac1 and its effector p-21 activated kinase (PAK), two enzymes critically involved in actin management and functional synaptic plasticity, is impaired at hippocampal synapses in the Fmr1-knock-out (KO) mouse model of FXS. Theta burst afferent stimulation (TBS) caused a marked increase in the number of synapses associated with phosphorylated PAK in adult hippocampal slices from wild-type, but not Fmr1-KO, mice. Stimulation-induced activation of synaptic Rac1 was also absent in the mutants. The polymerization of spine actin that occurs immediately after theta stimulation appeared normal in mutant slices but the newly formed polymers did not properly stabilize, as evidenced by a prolonged vulnerability to a toxin (latrunculin) that disrupts dynamic actin filaments. Latrunculin also reversed long-term potentiation when applied at 10 min post-TBS, a time point at which the potentiation effect is resistant to interference in wild-type slices. We propose that a Rac>PAK signaling pathway needed for rapid stabilization of activity-induced actin filaments, and thus for normal spine morphology and lasting synaptic changes, is defective in FXS.
Lobster Attack Induces Sensitization in the Sea Hare,Aplysia californica
Authors: Watkins Amanda J. , Goldstein Daniel A. , Lee Lucy C. , Pepino Christina J. , Tillett Scott L. , Ross Francis E. , Wilder Elizabeth M. , Zachary Virginia A. , Wright William G.
Published: August 2010

Studies of the neural mechanisms of learning, especially of sensitization, have benefitted from extensive research on the model species,Aplysia californica(hereafterAplysia). Considering this volume of literature on mechanisms, it is surprising that our understanding of the ecological context of sensitization inAplysiais completely lacking. Indeed, the widespread use of strong electric shock to induce sensitization (an enhancement of withdrawal reflexes following noxious stimulation) is completely unnatural and leaves unanswered the question of whether this simple form of learning has any ecological relevance. We hypothesized that sublethal attack by a co-occurring predator, the spiny lobster,Panulirus interruptus, might be a natural sensitizing stimulus. We tested reflex withdrawal of the tail-mantle and head of individualAplysiabefore and after attack by lobsters. Lobster attack significantly increased the amplitude of both reflexes, with a temporal onset that closely matched that observed with electric shock. This result suggests that electric shock may indeed mimic at least one naturally occurring sensitizing stimulus, suggesting, for the first time, an ecological context for this well studied form of learning.
Sonic Hedgehog Guides Post-Crossing Commissural Axons Both Directly and Indirectly by Regulating Wnt Activity
Authors: Domanitskaya Elena , Wacker Andrin , Mauti Olivier , Baeriswyl Thomas , Esteve Pilar , Bovolenta Paola , Stoeckli Esther T.
Published: August 2010

After midline crossing, axons of dorsolateral commissural neurons turn rostrally into the longitudinal axis of the spinal cord. In mouse, the graded distribution of Wnt4 attracts post-crossing axons rostrally. In contrast, in the chicken embryo, the graded distribution of Sonic hedgehog (Shh) guides post-crossing axons by a repulsive mechanism mediated by hedgehog-interacting protein. Based on these observations, we tested for a possible cooperation between the two types of morphogens. Indeed, we found that Wnts also act as axon guidance cues in the chicken spinal cord. However, in contrast to the mouse,Wnttranscription did not differ along the anteroposterior axis of the spinal cord. Rather, Wnt function was regulated by a gradient of the Wnt antagonist Sfrp1 (Secreted frizzled-related protein 1) that in turn was shaped by the Shh gradient. Thus, Shh affects post-crossing axon guidance both directly and indirectly by regulating Wnt function.
Role of Aberrant Striatal Dopamine D1Receptor/cAMP/Protein Kinase A/DARPP32 Signaling in the Paradoxical Calming Effect of Amphetamine
Authors: Napolitano Francesco , Bonito-Oliva Alessandra , Federici Mauro , Carta Manolo , Errico Francesco , Magara Salvatore , Martella Giuseppina , Nisticò Robert , Centonze Diego , Pisani Antonio , Gu Howard H. , Mercuri Nicola B. , Usiello Alessandro
Published: August 2010

Attention deficit/hyperactivity disorder (ADHD) is characterized by inattention, impulsivity, and motor hyperactivity. Several lines of research support a crucial role for the dopamine transporter (DAT) gene in this psychiatric disease. Consistently, the most commonly prescribed medications in ADHD treatment are stimulant drugs, known to preferentially act on DAT. Recently, a knock-in mouse [DAT-cocaine insensitive (DAT-CI)] has been generated carrying a cocaine-insensitive DAT that is functional but with reduced dopamine uptake function. DAT-CI mutants display enhanced striatal extracellular dopamine levels and basal motor hyperactivity. Herein, we showed that DAT-CI animals present higher striatal dopamine turnover, altered basal phosphorylation state of dopamine and cAMP-regulated phosphoprotein 32 kDa (DARPP32) at Thr75 residue, but preserved D2receptor (D2R) function. However, although we demonstrated that striatal D1receptor (D1R) is physiologically responsive under basal conditions, its stimulus-induced activation strikingly resulted in paradoxical electrophysiological, behavioral, and biochemical responses. Indeed, in DAT-CI animals, (1) striatal LTP was completely disrupted, (2)R-(+)-6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF 81297) treatment induced paradoxical motor calming effects, and (3) SKF 81297 administration failed to increase cAMP/protein kinase A (PKA)/DARPP32 signaling. Such biochemical alteration selectively affected dopamine D1Rs since haloperidol, by blocking the tonic inhibition of D2R, unmasked a normal activation of striatal adenosine A2Areceptor-mediated cAMP/PKA/DARPP32 cascade in mutants. Most importantly, our studies highlighted that amphetamine, nomifensine, and bupropion, through increased striatal dopaminergic transmission, are able to revert motor hyperactivity of DAT-CI animals. Overall, our results suggest that the paradoxical motor calming effect induced by these drugs in DAT-CI mutants depends on selective aberrant phasic activation of D1R/cAMP/PKA/DARPP32 signaling in response to increased striatal extracellular dopamine levels.
The α-Syntrophin PH and PDZ Domains Scaffold Acetylcholine Receptors, Utrophin, and Neuronal Nitric Oxide Synthase at the Neuromuscular Junction
Authors: Adams Marvin E. , Anderson Kendra N. E. , Froehner Stanley C.
Published: August 2010

At the neuromuscular junction (NMJ), the dystrophin protein complex provides a scaffold that functions to stabilize acetylcholine receptor (AChR) clusters. Syntrophin, a key component of that scaffold, is a multidomain adapter protein that links a variety of signaling proteins and ion channels to the dystrophin protein complex. Without syntrophin, utrophin and neuronal nitric oxide synthase μ (nNOSμ) fail to localize to the NMJ and the AChRs are distributed abnormally. Here we investigate the contribution of syntrophin domains to AChR distribution and to localization of utrophin and nNOSμ at the NMJ. Transgenic mice expressing α-syntrophin lacking portions of the first pleckstrin homology (PH) domain (ΔPH1a or ΔPH1b) or the entire PDZ domain (ΔPDZ) were bred onto the α-syntrophin null background. As expected the ΔPDZ transgene did not restore the NMJ localization of nNOS. The ΔPH1a transgene did restore postsynaptic nNOS but surprisingly did not restore sarcolemmal nNOS (although sarcolemmal aquaporin-4 was restored). Mice lacking the α-syntrophin PDZ domain or either half of the PH1 domain were able to restore utrophin to the NMJ but did not correct the aberrant AChR distribution of the α-syntrophin knock-out mice. However, mice expressing both the transgenic ΔPDZ and the transgenic ΔPH1a constructs did restore normal AChR distribution, demonstrating that both domains are required but need not be confined within the same protein to function. We conclude that the PH1 and PDZ domains of α-syntrophin work in concert to facilitate the localization of AChRs and nNOS at the NMJ.
A Temporal Hierarchy for Conspecific Vocalization Discrimination in Humans
Authors: De Lucia Marzia , Clarke Stephanie , Murray Micah M.
Published: August 2010

The ability to discriminate conspecific vocalizations is observed across species and early during development. However, its neurophysiologic mechanism remains controversial, particularly regarding whether it involves specialized processes with dedicated neural machinery. We identified spatiotemporal brain mechanisms for conspecific vocalization discrimination in humans by applying electrical neuroimaging analyses to auditory evoked potentials (AEPs) in response to acoustically and psychophysically controlled nonverbal human and animal vocalizations as well as sounds of man-made objects. AEP strength modulations in the absence of topographic modulations are suggestive of statistically indistinguishable brain networks. First, responses were significantly stronger, but topographically indistinguishable to human versus animal vocalizations starting at 169–219 ms after stimulus onset and within regions of the right superior temporal sulcus and superior temporal gyrus. This effect correlated with another AEP strength modulation occurring at 291–357 ms that was localized within the left inferior prefrontal and precentral gyri. Temporally segregated and spatially distributed stages of vocalization discrimination are thus functionally coupled and demonstrate how conventional views of functional specialization must incorporate network dynamics. Second, vocalization discrimination is not subject to facilitated processing in time, but instead lags more general categorization by ∼100 ms, indicative of hierarchical processing during object discrimination. Third, although differences between human and animal vocalizations persisted when analyses were performed at a single-object level or extended to include additional (man-made) sound categories, at no latency were responses to human vocalizations stronger than those to all other categories. Vocalization discrimination transpires at times synchronous with that of face discrimination but is not functionally specialized.
Memantine Preferentially Blocks Extrasynaptic over Synaptic NMDA Receptor Currents in Hippocampal Autapses
Authors: Xia Peng , Chen Huei-sheng Vincent , Zhang Dongxian , Lipton Stuart A.
Published: August 2010

Glutamate is the major excitatory neurotransmitter in the brain. The NMDA subtype of glutamate receptors (NMDAR) is known to mediate many physiological neural functions. However, excessive activation of NMDARs contributes to neuronal damage in various acute and chronic neurological disorders. To avoid unwanted adverse side effects, blockade of excessive NMDAR activity must therefore be achieved without affecting its physiological function. Memantine, an adamantane derivative, has been used for the treatment of Alzheimer's disease with an excellent clinical safety profile. We previously showed that memantine preferentially blocked neurotoxicity mediated by excessive NMDAR activity while relatively sparing normal neurotransmission, in part because of its uncompetitive antagonism with a fast off-rate. Here, using rat autaptic hippocampal microcultures, we show that memantine at therapeutic concentrations (1–10 μm) preferentially blocks extrasynaptic rather than synaptic currents mediated by NMDARs in the same neuron. We found that memantine blocks extrasynaptic NMDAR-mediated currents induced by bath application of 100 μmNMDA/10 μmglycine with a twofold higher potency than its blockade of the NMDAR component of evoked EPSCs (EPSCsNMDAR); this effect persists under conditions of pathological depolarization in the presence of 1 mmextracellular Mg2+. Thus, our findings provide the first unequivocal evidence to explain the tolerability of memantine based on differential extrasynaptic/synaptic receptor blockade. At therapeutic concentrations, memantine effectively blocks excessive extrasynaptic NMDAR-mediated currents, while relatively sparing normal synaptic activity.
Mechanisms of Regulation of Oligodendrocyte Development by p38 Mitogen-Activated Protein Kinase
Authors: Chew Li-Jin , Coley William , Cheng Ying , Gallo Vittorio
Published: August 2010

Many extracellular and intrinsic factors regulate oligodendrocyte development, but their signaling pathways remain poorly understood. Although the p38 mitogen-activated protein kinase (MAPK)-dependent pathway is implicated in oligodendrocyte progenitor cell (OPC) lineage progression, its molecular targets involved in myelinogenesis are mostly unidentified. We have analyzed mechanisms by which p38MAPK regulates oligodendrocyte development and demonstrate that p38MAPK inhibition prevents OPC lineage progression and inhibits MBP (myelin basic protein) promoter activity and Sox10 function. In white-matter tissue, differential levels of MAPK phosphorylation are observed in oligodendrocyte lineage cells. Phosphorylated p38MAPK was found in CC1- and CNP-expressing differentiated oligodendrocytes of the adult brain and was temporally associated with a decline in the levels of phosphorylated extracellular signal-regulated kinase (ERK) in cells of this lineage. PDGF stimulates the phosphorylation of ERK, p38MAPK, and c-Jun N-terminal kinase (JNK), and p38MAPK inhibition was associated with increased ERK, JNK, and c-Jun phosphorylation. In the presence of PDGF, simultaneous inhibition of p38MAPK and either MAPK kinase (MEK) or JNK significantly alleviates the repression of myelin gene expression and lineage progression induced by p38MAPK inhibition alone. Dominant-negative c-Jun reverses the inhibition of myelin promoter activity by active MEK1 or dominant-negative p38MAPKα mutants, and phosphorylated c-Jun was detected at the MBP promoter after p38MAPK inhibition, indicating c-Jun as a negative mediator of p38MAPK action. Our findings indicate that p38MAPK activity in the brain supports myelin gene expression through distinct mechanisms via positive and negative regulatory targets. We show that oligodendrocyte differentiation involves p38-mediated Sox10 regulation and cross talk with parallel ERK and JNK pathways to repress c-Jun activity.
Separable Prefrontal Cortex Contributions to Free Recall
Authors: Long Nicole M. , Öztekin Ilke , Badre David
Published: August 2010

In everyday life, we often must remember the past in the absence of helpful cues in the environment. In these cases, the brain directs retrieval by relying on internally maintained cues and strategies. Free recall is a widely used behavioral paradigm for studying retrieval with minimal cue support. During free recall, individuals often recall semantically related items consecutively—an effect termed semantic clustering—and previous studies have sought to understand clustering to gain leverage on the basic mechanisms supporting strategic recall. Successful recall and semantic clustering depend on the prefrontal cortex (PFC). However, as a result of methodological limitations, few functional magnetic resonance imaging (fMRI) studies have assessed the neural mechanisms at encoding that support subsequent recall, and none have tested the event-related correlates of recall itself. Thus, it remains open whether one or several frontal control mechanisms operate during encoding and recall. Here, we applied a recently developed method (Öztekin et al., 2010) to assess event-related fMRI signal changes during free recall. During encoding, dorsolateral prefrontal cortex (DLPFC) activation was predictive of subsequent semantic clustering. In contrast, subregions of ventrolateral prefrontal cortex (VLPFC) were predictive of subsequent recall, whether clustered or nonclustered, and were inversely associated with clustering during recall. These results suggest that DLPFC supports relational processes at encoding that are sufficient to produce category clustering effects during recall. Conversely, controlled retrieval mechanisms supported by VLPFC support item-specific search during recall.
Decreased Rhythmic GABAergic Septal Activity and Memory-Associated θ Oscillations after Hippocampal Amyloid-β Pathology in the Rat
Authors: Villette Vincent , Poindessous-Jazat Frédérique , Simon Axelle , Léna Clément , Roullot Elodie , Bellessort Brice , Epelbaum Jacques , Dutar Patrick , Stéphan Aline
Published: August 2010

The memory deficits associated with Alzheimer's disease result to a great extent from hippocampal network dysfunction. The coordination of this network relies on theta (θ) oscillations generated in the medial septum. Here, we investigated in rats the impact of hippocampal amyloid β (Aβ) injections on the physiological and cognitive functions that depend on the septohippocampal system. Hippocampal Aβ injections progressively impaired behavioral performances, the associated hippocampal θ power, and θ frequency response in a visuospatial recognition test. These alterations were associated with a specific reduction in the firing of the identified rhythmic bursting GABAergic neurons responsible for the propagation of the θ rhythm to the hippocampus, but without loss of medial septal neurons. Such results indicate that hippocampal Aβ treatment leads to a specific functional depression of inhibitory projection neurons of the medial septum, resulting in the functional impairment of the temporal network.
Premature ovarian failure
Authors: Shelling Andrew N
Published: August 2010

Premature ovarian failure (POF) is a common cause of infertility in women, and is characterised by amenorrhoea, hypo-oestrogenism and elevated gonadotrophin levels in women under the age of 40. Known causes include iatrogenic agents that cause permanent damage to the ovaries, such as chemotherapy, radiation therapy and surgery, autoimmune conditions, X-chromosome abnormalities and autosomal genetic conditions. However, few genes have been identified that can explain a substantial proportion of cases of POF. Most women with POF are deeply upset by the diagnosis, partly due to the unexpected menopausal symptoms, but also due to infertility. Therefore, early detection would provide better opportunity for early intervention, and furthermore, the identification of specific gene defects will help to direct potential targets for future treatment.
TiO2 Nanotube Films via Laser Ablation for Solar Cells
Authors: Perara Sanjaya D. , Balkus Kenneth
Published: August 2010

Titanium dioxide (TiO2) nanostructures are widely employed in photoconversion processes. In particular titanium dioxide nanotubes (TNTs) have shown promise in many applications including solar cells. While there are methods for making TNT films the preparation of high surface area small diameter (<10nm) TNT films is a challenge. We have now prepared TNT films by pulsed laser deposition (PLD) of P25 and P90 TiO2TiO2 nanoparticles onto stainless steel foils followed by a hydrothermal treatment. The best results were obtained when the TiO2TiO2 films were deposited at 500°C. Subsequent hydrothermal treatment at 150°C results in a dense mat of TNTs that are ˜10 nm in diameter with a pore size of ˜5 nm. The TNTs were further functionalized with quantum dots including PbS with controlled particle size and location to access a greater portion of the solar spectrum. The titanium oxide nanotube/ quantum dot films were characterized by SEM, TEM, XRD UV-Vis and Raman spectroscopy. Preliminary results for the formation and characterization of solar cells using the TNT films will be described.
Comparative Stress Distribution of Implant-Retained Mandibular Ball-Supported and Bar-Supported Overlay Dentures: A Finite Element Analysis
Authors: Vafaei Fariborz , Khoshhal Masoumeh , Bayat-Movahed Saeed , Ahangary Ahmad Hassan , Firooz Farnaz , Izady Alireza , Rakhshan Vahid
Published: August 2010

Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.
Botulinum toxin type A in the treatment of hemifacial spasm: an 11-year experience
Authors: Barbosa Egberto Reis , Takada Leonel Tadao , Gonçalves Lilian Regina , Costa Rose Mary Paulo do Nascimento , Silveira-Moriyama Laura , Chien Hsin Fen
Published: August 2010

In order to evaluate the long-term effect of botulinum toxin type A (BTX) in the treatment of hemifacial spasm (HFS), a retrospective analysis of patients treated at the Movement Disorders Unit of the Division of Neurology, Clinical Hospital, University of São Paulo, School of Medicine from 1993 to 2004 was made. A total of 808 injections with BTX were administered to 54 patients with HFS. The mean duration of improvement per application was 3.46 months and the mean rate of improvement using subjective judgement by the patient was of 83%. Adverse effects, mostly minor, were observed in 64.8% of patients at least once along the period of follow-up and the most frequent of them was orbicularis oris paralysis (38.8%). There was no decrement in response when compared the first and the last injection recorded.
Impact of autologous hematopoetic stem cell transplantation on the quality of life of patients with multiple sclerosis
Authors: Guimarães Fabio Augusto Bronzi , Oliveira-Cardoso Érika Arantes de , Mastropietro Ana Paula , Voltarelli Júlio César , Santos Manoel Antônio dos
Published: August 2010

OBJECTIVE: To evaluate the impact of autologous hematopoetic stem cell transplantation (autoHSCT) in the health related quality of life (HRQL) in patients with multiple sclerosis. METHOD: The sample consisted of 34 patients, over 18 years old, treated at a University Hospital in the state of São Paulo, Brazil. For data collection MOS SF-36 and EDSS scales were applied at three time points: admission of the patient, hospital discharge and 1 year posttransplantation. RESULTS: 27 patients (79%) showed stabilization or neurological improvement 1 year posttransplantation. At this time point, there was statistically significant improvement in all domains of the HRQoL. When EDSS scores were correlated with the domains of the MOS SF-36 scale, statistically significant correlations were found with physical functioning at the three time points analysed. CONCLUSION: In spite of the high risk of complications of the procedure, the HSCT had positive impact in the health related quality of life.
Attention deficit/hyperactivity disorder symptoms in indigenous children from the Brazilian Amazon
Authors: Azevêdo Paulo Verlaine Borges e , Caixeta Leonardo , Andrade Laura Helena Silveira , Bordin Isabel A
Published: August 2010

The clinical constructs of attention deficit/hyperactivity disorder (ADHD) have been described in several cultures worldwide. Yet this symptomatic presentation still remains to be assessed in remote population groups. OBJECTIVE: To explore the possibility of the existence of ADHD symptoms among settlement-dwelling indigenous children of the Karajá ethnic group in the Brazilian Amazon and to estimate the rate of ADHD symptoms among 7-16-year-olds. METHOD: All parents/caretakers of 7-16-year olds from all (N=5) most populated indigenous groups were invited to participate, if they were worried about their children emotional/behavioural problems. Fifty three parents spontaneously came for a psychiatric interview (DSM-IV criteria applied), individually conducted at the settlement's health post by a child psychiatrist. RESULTS: The estimated rate of ADHD symptoms in problematic indigenous children aged 7-16 years was 24.5% (95% CI: 13.6-35.4) since 13 out of 53 parents/caretakers reported the classical triad of ADHD symptoms (inattentiveness, hyperactivity, impulsiveness). CONCLUSION: ADHD is a clinically relevant construct in the Karajá indigenous population, representing a major concern among parents/caretakers of children and adolescents from this ethnic group.
A thioacetamide-induced hepatic encephalopathy model in C57BL/6 mice: a behavioral and neurochemical study
Authors: Miranda Aline Silva de , Rodrigues David Henrique , Vieira Luciene Bruno , Lima Cristiano Xavier , Rachid Milene Alvarenga , Vidigal Paula Vieira Teixeira , Gomez Marcus Vinicius , Reis Helton José dos , Guatimosim Cristina , Teixeira Antônio Lúcio
Published: August 2010

OBJECTIVE: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome resulting from liver failure. In the present study, we aimed to standardize an animal model of HE induced by thioacetamide (TAA) in C57BL/6 mice evaluating behavioral symptoms in association with liver damage and alterations in neurotransmitter release. METHOD: HE was induced by an intraperitoneal single dose of TAA (200 mg/kg, 600 mg/kg or 1,200 mg/kg). Behavioral symptoms were evaluated using the SHIRPA battery. Liver damage was confirmed by histopathological analysis. The glutamate release was measured using fluorimetric assay. RESULTS: The neuropsychiatric state, motor behavior and reflex and sensory functions were significantly altered in the group receiving 600 mg/kg of TAA. Biochemical analysis revealed an increase in the glutamate release in the cerebral cortex of HE mice. CONCLUSION: HE induced by 600mg/kg TAA injection in C57BL/6 mice seems to be a suitable model to investigate the pathogenesis and clinical disorders of HE.
Caspase-3 and Bcl-2 expression in glioblastoma: an immunohistochemical study
Authors: Tirapelli Luís Fernando , Bolini Paulo Henrique Nasser Andre , Tirapelli Daniela Pretti da Cunha , Peria Fernanda Maris , Becker Aline Nazareth Paixão , Saggioro Fabiano Pinto , Carlotti Júnior Carlos Gilberto
Published: August 2010

The unfavorable prognosis of malignant gliomas can also be explained by the incomplete knowledge of their molecular pathways. Studies regarding the regulatory process of apoptosis in glioblastoma (GBM), the most common malignant glioma, are few, and better knowledge of the expression of pro and anti-apoptotic proteins could collaborate with the development of new treatments founded on molecular basis. The objective of this study was to evaluate by immunohistochemistry the expression of caspase-3 and Bcl-2 in 30 samples of GBMs. The expression of caspase-3 (mean 17.67%) was lower than Bcl-2 (mean 30.92%), a statistically significant result (p<0.0001), suggesting low apoptotic activity in these tumors. Other studies of proteins related to the intrinsic and extrinsic pathway of apoptosis are required to provide additional information of this mechanism in GBMs.
Temporal branch of facial nerve: a normative study of nerve conduction
Authors: Silva Paula Fabiana Sobral da , Lima Maria Carolina Martins de , Figueiroa José Natal , Lins Otávio Gomes
Published: August 2010

The temporal branch of the facial nerve is particularly vulnerable to traumatic injuries during surgical procedures. It may also be affected in clinical conditions. Electrodiagnostic studies may add additional information about the type and severity of injuries, thus allowing prognostic inferences. The objective of the present study was to develop and standardize an electrophysiological technique to specifically evaluate the temporal branch of the facial nerve. METHOD: Healthy volunteers (n=115) underwent stimulation of two points along the nerve trajectory, on both sides of the face. The stimulated points were distal (on the temple, over the temporal branch) and proximal (in retro-auricular region). Activities were recorded on the ipsilateral frontalis muscle. The following variables were studied: amplitude (A), distal motor latency (DML) and conduction velocity (NCV). RESULTS: Differences between the sides were not significant. The proposed reference values were: A >0.4 mV, DML <3.9 ms and NCV >40 m/s. Variation between hemifaces should account for less than 60% for amplitudes and latency, and should be inferior to 20% for conduction velocity. CONCLUSION: These measurements are an adequate way for proposing normative values for the electrophysiological evaluation of the temporal branch.
Patent foramen ovale in trigeminal autonomic cephalalgias and hemicrania continua: a non-specific pathophysiological occurrence?
Authors: Amaral Vanise , Freitas Gabriel R. de , Rodrigues Bruno C.B , Christoph Daniel de H , Pinho Carlos A. de , Góes Cristiana de Faria P , Vincent Maurice B
Published: August 2010

Patent foramen ovale (PFO), a relatively common abnormality in adults, has been associated with migraine. Few studies also linked PFO with cluster headache (CH). To verify whether right-to-left shunt (RLS) is related to headaches other than migraine and CH, we used transcranial Doppler following microbubbles injection to detect shunts in 24 CH, 7 paroxysmal hemicrania (PH), one SUNCT, two hemicrania continua (HC) patients; and 34 matched controls. RLS was significantly more frequent in CH than in controls (54% vs. 25%, p=0.03), particularly above the age of 50. In the HC+PH+SUNCT group, RLS was found in 6 patients and in 2 controls (p=0.08). Smoking as well as the Epworth Sleepiness Scale correlated significantly with CH, smoking being more frequent in patients with RLS. PFO may be non-specifically related to trigeminal autonomic cephalalgias and HC. The headache phenotype in PFO patients probably depends on individual susceptibility to circulating trigger factors.
How many Babinski's signs are there?
Authors: Kakitani Fabio T , Collares Daniel , Kurozawa Adam Y , Lima Plínio M.G. de , Teive Hélio A.G
Published: August 2010

In addition to the famous sign described by Joseph Babinski, which is also known as Babinski's reflex, there are references in the literature to various other signs described by this famous disciple of J-M Charcot. This article reviews all the neurological signs described by Babinski.
Cinética da secagem de clones de café (Coffea canephora Pierre) em terreiro de chão batido
Authors: Resende Osvaldo , Rodrigues Silvestre , Siqueira Valdiney Cambuy , Arcanjo Renan Vieira
Published: August 2010

Objetivou-se com o presente trabalho estudar a cinética da secagem de quatro clones de café da espécie Coffea canephora submetidos à secagem em terreiro de chão batido, bem como ajustar diferentes modelos matemáticos aos valores experimentais selecionando aquele que melhor representa o fenômeno em estudo. Foram utilizados frutos de café dos clones: Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro180, colhidos com os teores de água iniciais de 1,20; 1,32; 1,51 e 1,46 (decimal base seca (b.s.)), respectivamente. A secagem prosseguiu em terreiro de chão batido até que o produto atingisse o teor de água de 0,137; 0,133; 0,142 e 0,140 (decimal b.s.) respectivamente para os clones Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro 180. Aos dados experimentais foram ajustados dez modelos matemáticos citados na literatura específica e utilizados para representação do processo de secagem de produtos agrícolas. Baseando-se em parâmetros estatísticos, conclui-se que os modelos Verma, Dois Termos e Aproximação da Difusão foram adequados para representação da secagem dos quatro clones de café analisados, e além destes, para o clone Cpafro 167, os modelos Thompson, Page, Newton, Logarítmico, Henderson e Pabis e Exponencial de Dois Termos também se mostraram satisfatórios na descrição do fenômeno; já o tempo necessário para a secagem em terreiro de chão batido dos clones de café Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro 180 foi de 189,5 h.
Actinella species (Bacillariophyta) from an Amazon black water floodplain lake (Amazonas - Brazil)
Authors: Melo Sérgio , Torgan Lezilda Carvalho , Raupp Stela Valenti
Published: August 2010

The genus Actinella Lewis was studied using planktonic samples from a black water floodplain lake in Central Amazon region. For species identification the taxa were morphological and morphometricaly analyzed on base in light microscope (LM) and scanning electronic microscope (SEM). Five species were registered: Actinella brasiliensis Grunow, A. guianensis Grunow, A. gracile Kociolek, A. mirabilis (Eulenstein ex Grunow) Grunow and A. robusta Hustedt. A. gracile is reported for the first time for Amazon State and black water systems and it is firstly documented with SEM. In addition, a review of geographic distribution of Actinella species in Brazilian Amazon region is given.
Population Dynamics Modeling of Arapaima gigas
Authors: Coutinho Eliane dos Santos de Souza , Bevilacqua Luiz , Queiroz Helder Lima de
Published: August 2010

Pirarucu (Arapaima gigas) has been of the most important natural fishing resources of the Amazon region. Due to its economic importance, and the necessity to preserve the species hand, field research concerning the habits and behavior of the pirarucu has been increasing for the last 20 years. The aim of this paper is to present a mathematical model for the pirarucu population dynamics considering the species peculiarities, particularly the male parental care over the offspring. The solution of the dynamical systems indicates three possible equilibrium points for the population. The first corresponds to extinction; the third corresponds to a stable population close to the environmental carrying capacity. The second corresponds to an unstable equilibrium located between extinction and full use of the carrying capacity. It is shown that lack of males’ parental care closes the gap between the point corresponding to the unstable equilibrium and the point of stable non-trivial equilibrium. If guarding failure reaches a critical point the two points coincide and the population tends irreversibly to extinction. If some event tends to destabilize the population equilibrium, as for instance inadequate parental care, the model responds in such a way as to restore the trajectory towards the stable equilibrium point avoiding the route to extinction. The parameters introduced to solve the system of equations are partially derived from limited but reliable field data collected at the Mamirauá Sustainable Development Reserve (MSDR) in the Brazilian Amazonian Region.
Inquérito sobre o reinício da atividade ovariana no pós-parto de vacas leiteiras através da dosagem de progesterona no leite
Authors: Meirelles CF. , Abdalla A.L. , Vitti D.M.S.S. , Silva Filho J.C.
Published: August 2010

Com o intuito de determinar o reinício da atividade ovariana no pós-parto em vacas leiteiras, foi realizado um estudo em uma propriedade particular na região de Rio das Pedras, São Paulo. Durante 12 meses, amostras de leite foram coletadas semanalmente e o teor de progesterona determinado através de radioimunoensaio. Observou-se que 26,6% das vacas permaneceram em anestro e que ocorreram falhas nas observações de cio. A maioria dos animais (61,1%) apresentou atividade ovariana com 31 à 60 dias de pós-parto.