bluuebunny/crossref_metadata_2025 huggingface dataset:
Eye movements and visuoverbal descriptions exhibit heterogeneous and dissociated patterns before and after prismatic adaptation in unilateral spatial neglect
Authors: Datié A.‐M. , Paysant J. , Destainville S. , Sagez A. , Beis J.‐M. , André J.‐M.
Published: May 2006

This prospective study examined the effects of prismatic adaptation on visual exploration strategies in patients with left unilateral spatial neglect (USN). Photo‐oculographic gaze recordings were obtained, as the subjects (28 brain‐damaged; 15 control) performed a free visual exploration task before and after a session of prismatic adaptation. (i) Before prismatic adaptation, the pattern of visual exploration described two subgroups of patients (symmetrical exploration of hemispaces – similar to the control subjects, deficient exploration of left hemispace). Twelve of 20 patients failed to describe significant elements in the left part of the displayed image. Several visuoverbal patterns were observed, some dissociating visual exploration and verbal description. (ii) Immediately after prismatic adaptation, patients with asymmetrical visual exploration presented a significant increase in the number of point fixations and saccades in the left hemispace. Patients with symmetrical exploration presented the opposite pattern. Improved pattern of visual exploration contrasted with an absence of improved verbal description. Eye movements and visuoverbal descriptions exhibit heterogeneous and dissociated patterns before and after prismatic adaptation. This results demonstrate that prismatic adaptation has no effect in certain patients, suggesting that therapeutic indications and evaluation of prismatic test results should take into consideration the heterogeneous nature of USN.
Protection against glucose‐induced neuronal death by NAAG and GCP II inhibition is regulated by mGluR3
Authors: Berent‐Spillson Alison , Robinson Amanda M. , Golovoy David , Slusher Barbara , Rojas Camilo , Russell James W.
Published: May 2006

Glutamate carboxypeptidase II (GCP II) inhibition has previously been shown to be protective against long‐term neuropathy in diabetic animals. In the current study, we have determined that the GCP II inhibitor 2‐(phosphonomethyl) pentanedioic acid (2‐PMPA) is protective against glucose‐induced programmed cell death (PCD) and neurite degeneration in dorsal root ganglion (DRG) neurons in a cell culture model of diabetic neuropathy. In this model, inhibition of caspase activation is mediated through the group II metabotropic glutamate receptor, mGluR3. 2‐PMPA neuroprotection is completely reversed by the mGluR3 antagonist (S)‐α‐ethylglutamic acid (EGLU). In contrast, group I and III mGluR inhibitors have no effect on 2‐PMPA neuroprotection. Furthermore, we show that two mGluR3 agonists, the direct agonist (2R,4R)‐4‐aminopyrrolidine‐2, 4‐dicarboxylate (APDC) and N‐acetyl‐aspartyl‐glutamate (NAAG) provide protection to neurons exposed to high glucose conditions, consistent with the concept that 2‐PMPA neuroprotection is mediated by increased NAAG activity. Inhibition of GCP II or mGluR3 may represent a novel mechanism to treat neuronal degeneration under high‐glucose conditions.
Putative endogenous mediators of preconditioning‐induced ischemic tolerance in rat brain identified by genomic and proteomic analysis
Authors: Dhodda Vinay K. , Sailor Kurt A. , Bowen Kellie K. , Vemuganti Raghu
Published: May 2006

In brain, a brief ischemic episode induces protection against a subsequent severe ischemic insult. This phenomenon is known as preconditioning‐induced neural ischemic tolerance. An understanding of the molecular mechanisms leading to preconditioning helps in identifying potential therapeutic targets for preventing the post‐stroke brain damage. The present study conducted the genomic and proteomic analysis of adult rat brain as a function of time following preconditioning induced by a 10‐min transient middle cerebral artery (MCA) occlusion. GeneChip analysis showed induction of 40 putative neuroprotective transcripts between 3 to 72 h after preconditioning. These included heat‐shock proteins, heme oxygenases, metallothioneins, signal transduction mediators, transcription factors, ion channels and apoptosis/plasticity‐related transcripts. Real‐time PCR confirmed the GeneChip data for the transcripts up‐regulated after preconditioning. Two‐dimensional gel electrophoresis combined with MALDI‐TOF analysis showed increased expression of HSP70, HSP27, HSP90, guanylyl cyclase, muskelin, platelet activating factor receptor and β‐actin at 24 h after preconditioning. HSP70 protein induction after preconditioning was localized in the cortical pyramidal neurons. The infarct volume induced by focal ischemia (1‐h MCA occlusion) was significantly smaller (by 38 ± 7%,p < 0.05) in rats subjected to preconditioning 3 days before the insult. Preconditioning also prevented several gene expression changes induced by focal ischemia.
Mitochondrial extracellular signal‐regulated kinases 1/2 (ERK1/2) are modulated during brain development
Authors: Alonso Mariana , Melani Mariana , Converso Daniela , Jaitovich Ariel , Paz Cristina , Carreras M. Cecilia , Medina Jorge H. , Poderoso Juan J.
Published: May 2006

Intracellular activation and trafficking of extracellular signal‐regulated protein kinases (ERK) play a significant role in cell cycle progression, contributing to developmental brain activities. Additionally, mitochondria participate in cell signalling through energy‐linked functions, redox metabolism and activation of pro‐ or anti‐apoptotic proteins. The purpose of the present study was to analyze the presence of ERK1/2 in mitochondria during rat brain development. Immunoblotting, immune electron microscopy and activity assays demonstrated that ERK1/2 are present in fully active brain mitochondria at the outer membrane/intermembrane space fraction. Besides, it was observed that ERK1/2 translocation to brain mitochondria follows a developmental pattern which is maximal between E19‐P2 stages and afterwards declines at P3, just before maximal translocation to nucleus, and up to adulthood. Most of mitochondrial ERK1/2 were active; upstream phospho‐MAPK/ERK kinases (MEK1/2) were also detected in the brain organelles. Mitochondrial phospho‐ERK1/2 increased at 1 μm hydrogen peroxide (H2O2) concentration, but it decreased at higher 50–100 μm H2O2, almost disappearing after the organelles were maximally stimulated to produce H2O2 with antimycin. Our results suggest that developmental mitochondrial activation of ERK1/2 cascade contributes to its nuclear translocation effects, providing information about mitochondrial energetic and redox status to the proliferating/differentiating nuclear pathways.
Platelet‐activating factor receptor‐deficient mice are protected from experimental sleep apnea‐induced learning deficits
Authors: Row Barry W. , Kheirandish Leila , Li Richard C. , Guo Shang Z. , Brittian Kenneth R. , Hardy Mattie , Bazan Nicolas G. , Gozal David
Published: May 2006

Intermittent hypoxia (IH) during sleep, a hallmark of sleep apnea, is associated with neurobehavioral impairments, regional neurodegeneration and increased oxidative stress and inflammation in rodents. Platelet‐activating factor (PAF) is an important mediator of both normal neural plasticity and brain injury. We report that mice deficient in the cell surface receptor for PAF (PAFR–/–), a bioactive mediator of oxidative stress and inflammation, are protected from the spatial reference learning deficits associated with IH. Furthermore, PAFR–/– exhibit attenuated elevations in inflammatory signaling (cyclo‐oxygenase‐2 and inducible nitric oxide synthase activities), degradation of the ubiquitin–proteasome pathway and apoptosis observed in wild‐type littermates (PAFR+/+) exposed to IH. Collectively, these findings indicate that inflammatory signaling and neurobehavioral impairments induced by IH are mediated through PAF receptors.
A Microdialysis Profile of Dynorphin A1–8 Release in the Rat Nucleus Accumbens Following Alcohol Administration
Authors: Marinelli Peter W. , Lam Minh , Bai Li , Quirion Rémi , Gianoulakis Christina
Published: May 2006

Background: Pharmacological studies have implicated the endogenous opioid system in mediating alcohol intake. Other evidence has shown that alcohol administration can influence endorphinergic and enkephalinergic activity, while very few studies have examined its effect on dynorphinergic systems. The aim of the present study was to investigate the effect of alcohol administration or a mechanical stressor on extracellular levels of dynorphin A1–8 in the rat nucleus accumbens—a brain region that plays a significant role in the processes underlying reinforcement and stress.

Methods: Male Sprague–Dawley rats were implanted with a microdialysis probe aimed at the shell region of the nucleus accumbens. Artificial cerebrospinal fluid was pumped at a rate of 1.5 μL/min in awake and freely moving animals and the dialysate was collected at 30‐minute intervals. In one experiment, following a baseline period, rats were injected intraperitoneally with either physiological saline or 1 of 3 doses of alcohol, 0.8, 1.6, or 3.2 g ethanol/kg body weight. In a second experiment, following a baseline period, rats were applied a clothespin to the base of their tail for 20 minutes. The levels of dynorphin A1–8 in the dialysate were analyzed with solid‐phase radioimmunoassay.

Results: Relative to saline‐treated controls, an alcohol dose of 1.6 and 3.2 g/kg caused a transient increase in the extracellular levels of dynorphin A1–8 in the first 30 minutes of alcohol administration. However, the effect resulting from the high 3.2 g/kg dose was far more pronounced and more significant than with the moderate dose. There was no effect of tail pinch on dynorphin A1–8 levels in the nucleus accumbens.

Conclusions: In this experiment, a very high dose of alcohol was especially capable of stimulating dynorphin A1–8 release in the nucleus accumbens. Dynorphin release in the accumbens has been previously associated with aversive stimuli and may thus reflect a system underlying the aversive properties of high‐dose alcohol administration. However, the lack of effect of tail‐pinch stress in the present study suggests that dynorphin A1–8 is not released in response to all forms of stressful/aversive stimuli.
Comparison of VTA Dopamine Neuron Activity in Lines of Rats Selectively Bred to Prefer or Avoid Alcohol
Authors: Morzorati Sandra L. , Marunde Rita L.
Published: May 2006

Background:Studies comparing alcohol‐naïve alcohol‐preferring (P) and ‐nonpreferring (NP) rats indicate that high alcohol drinking is associated with an innate deficiency of the mesolimbic dopamine (DA) system. We previously reported that ventral tegmental area (VTA) DA neurons in alcohol‐naïve P rats burst fire more frequently than VTA DA neurons in alcohol‐naïve Wistar rats. We hypothesized that increased burst firing in P rats may represent a compensatory mechanism to maintain adequate levels of DA in terminal areas, such as the nucleus accumbens, despite the deficient mesolimbic DA system. The present study sought to extend our previous work and include NP rats and to determine whether differences in VTA DA neuron activity could be generalized to other rat lines selected for high and low alcohol preference, namely the high (HAD) and low (LAD) alcohol‐drinking rats.

Methods:The extracellular activity of posterior VTA DA neurons was recorded in unanesthetized alcohol‐naïve rats from the P/NP and HAD/LAD lines. Firing frequencies, burst activity, and the number of DA neurons encountered per electrode track were compared.

Results:Dopamine neurons in the posterior VTA of P rats had a greater percentage of action potentials in bursts and greater number of bursts compared with posterior VTA DA neurons in NP rats. There were no differences in VTA DA neuronal activity between both replicate lines of HAD and LAD rats.

Conclusions:Burst activity of posterior VTA DA neurons distinguishes P from NP rats, but does not generalize to other lines of rats selectively bred at Indiana University for alcohol preference and nonpreference. Increased burst activity of DA neurons in the posterior VTA may be related to alcohol preference in P rats but is not necessary for high alcohol drinking.
Suicide Attempts Among Substance Use Disorder Patients: An Initial Step Toward a Decision Tree for Suicide Management
Authors: Tiet Quyen Q. , Ilgen Mark A. , Byrnes Hilary F. , Moos Rudolf H.
Published: May 2006

Background: Little empirical data are available to develop profiles of patients who attempt suicide or to formulate a decision tree for suicide management. This study identifies profiles of patients who have a high risk of suicide attempt and takes a first step toward developing a decision tree to classify high‐risk patients.

Methods: Based on a cross‐sectional, nationwide cohort of substance use disorder patients (N=34,251) in 150 Veterans Affairs (VA) facilities, a total of 5,671 patients who reported suicidal ideation in the 30 days before intake assessment were included in receiver operating characteristic (ROC) analyses to identify the 30‐day risk of an actual suicide attempt. Clinical diagnostic and Addiction Severity Index interview data were used.

Results: Results provide an initial decision tree to classify high‐risk patients with sensitivity ranging from 0.33 to 0.89, and specificity, from 0.42 to 0.87. The factors included in the decision tree encompass history of prior suicide attempts, current drinking to intoxication, current cocaine use, first occasion of suicidal ideation, and difficulty controlling violent behavior.

Conclusions: To our knowledge, this is the first attempt to use empirical data to provide information to eventually establish a decision tree for clinical management of patients with suicidal ideation. The findings show that profiles of patients who are at high risk of suicide attempts can be effectively identified using ROC, with relatively good sensitivity and specificity.
Possible Role of Nerve Growth Factor in the Pathogenesis of Alcohol Dependence
Authors: Yoon Su‐Jung , Roh Sungwon , Lee Heejin , Lee Ji‐Youl , Lee Bun‐Hee , Kim Yong‐Ku , Kim Dai‐Jin
Published: May 2006

Background: Recent studies have raised the possibility that nerve growth factor (NGF) is abnormally regulated in the central nervous system (CNS) of animal models of chronic ethanol treatment. The goals of this study were to determine whether prolonged alcohol consumption is associated with the plasma NGF levels and to assess the effect of a positive family history of alcohol dependence on plasma NGF levels in the alcohol‐dependent patients.

Methods: We used the enzyme‐linked immunosorbent assay (ELISA) to determine the concentrations of peripheral NGF in patients with alcohol dependence and in a control group.

Results: The plasma NGF concentrations in the alcohol‐dependent patients were significantly lower than in the controls (71.9 vs 110.5 pg/mL, respectively). Moreover, the alcohol‐dependent patients with positive family histories showed a greater decrease in their NGF levels than those subjects with negative family histories (64.7 vs 83.3 pg/mL, respectively).

Conclusions: Our study suggests that the NGF levels may be a trait marker for the development of alcohol dependence.
Course of Recovery from Alcoholism
Authors: Venner Kamilla L. , Matzger Helen , Forcehimes Alyssa A. , Moos Rudolf H. , Feldstein Sarah W. , Willenbring Mark L. , Weisner Constance
Published: May 2006

This article represents the proceedings of a symposium at the 2005 Research Society on Alcoholism meeting in Santa Barbara, California, organized and chaired by Kamilla L. Venner. This symposium integrated current empirical research on the course of recovery from alcoholism from multiple perspectives, an aim that is consistent with NIAAA's new focus on the process of recovery. The presentations and presenters were as follows: (1) The Role of Community Services and Informal Support on 7‐Year Drinking Outcomes in Treated and Untreated Drinkers, by Helen Matzger; (2) The Sequence of Recovery Events in a Native American Sample, by Kamilla L. Venner; (3) Transformational Change in Recovery, by Alyssa A. Forcehimes; (4) Social Settings and Substance Use: Contextual Factors in Recovery, by Rudolf H. Moos; and (5) A Broader View of Change in Drinking Behavior, by discussant Mark L. Willenbring. A theme connecting the presentations was that treatment is but one discrete aspect to recovery and that sustained recovery is often influenced by an individual interaction with others within a social context. Collectively, presentations underscored the need to think more broadly about factors contributing to the remission of alcohol dependence.
Relationship Between Level of Consumption and Harms in Assessing Drink Cut‐Points for Alcohol Research: Commentary on “Many College Freshmen Drink at Levels Far Beyond the Binge Threshold” by White et al.
Authors: Wechsler Henry , Nelson Toben F.
Published: May 2006

In this commentary, we describe the use of a 5/4 drink summary measure of heavy episodic alcohol consumption, or “binge” drinking, in survey research and its usefulness for preventing negative alcohol‐related consequences. Data from 4 nationally representative surveys of more than 50,000 college students are utilized to examine the utility of this measure in comparison with alternative cut‐points. Our analysis demonstrates that while higher drink threshold measures incrementally improve the ability to identify correctly students who experience harms or who meet DSM‐IV diagnostic criteria of alcohol abuse and dependence, they capture only a small proportion of those college students experiencing harms. We conclude that the selection of a measurement tool should be consistent with the purpose for which it is to be used. The 5/4 measure of binge drinking provides a valuable means for understanding and preventing alcohol‐related harms in a college population and can be utilized as a screen to identify students who may need additional clinical assessment for intervention.
Progress in Using Mouse Inbred Strains, Consomics, and Mutants to Identify Genes Related to Stress, Anxiety, and Alcohol Phenotypes
Authors: Goldowitz Daniel , Matthews Douglas B. , Hamre Kristin M. , Mittleman Guy , Chesler Elissa J. , Becker Howard C. , Lopez Marcelo F. , Jones Sara R. , Mathews Tiffany A. , Miles Michael F. , Kerns Robnet , Grant Kathleen A.
Published: May 2006

This article summarizes the proceedings of a symposium that took place at the 2005 meeting of the Research Society on Alcoholism. The organizers/chairs were Daniel Goldowitz and Katheen A. Grant. The presentations were as follows: (1) High‐Throughput Screening for Ethanol Phenotypes, by Douglas B. Matthews and Kristin M. Hamre; (2) Genetic Basis of Schedule‐Induced Polydipsia in Mice, by Guy Mittleman and Elissa J. Chesler; (3) Effects of Stress and Ethanol Dependence on Ethanol Self‐administration in Inbred and Mutant Mice, by Howard C. Becker and Marcelo F. Lopez; (4) Changes in Dopaminergic Mechanisms Associated With Ethanol Dependence, by Sara R. Jones and Tiffany A. Mathews; and (5) Defining Brain Region–Specific Gene Networks Relevant to Ethanol Behaviors, by Michael F. Miles and Robnet Kerns.
Regulating Chemicals—From Risks to Riskiness
Authors: Chapman Anne
Published: May 2006

Under current European Union legislation, action to restrict the production and use of a chemical is only justified if there is evidence that the chemical poses a risk to human health or the environment. Risk is understood as being a matter of the magnitude and probability of specifiable harms. An examination of how risks from chemicals are assessed shows the process to be fraught with uncertainty, with the result that evidence that commands agreement as to whether a chemical poses a risk or not is often not available. Hence the frequent disputes as to whether restrictions on chemicals are justified. Rather than trying to assess the risks from a chemical, I suggest that we should aim to assess how risky a chemical is in a more everyday sense, where riskiness is a matter of the possibility of harm. Risky chemicals are those where, given our state of knowledge, it is possible that they cause harm. I discuss four things that make a chemical more risky: (1) its capacity to cause harm; (2) its novelty; (3) its persistence; and (4) its mobility. Regulation of chemicals should aim to reduce the production and use of risky chemicals by requiring that the least risky substance or method is always used for any particular purpose. Any use of risky substances should be justifiable in terms of the public benefits of that use.
An improved approach for assigning pumping rates to heterogeneous aquifer models
Authors: Pinales Adan , Chavez Adolfo , Llerar Geronimo , Manzanares Luisa , Keer Arturo
Published: May 2006

A common assumption of ground water models formulated using a block‐centered finite‐difference method is that a well is located at the center of a cell regardless of its actual location. Due to this assumption, errors are introduced in the spatial distribution of simulated heads. This paper presents an alternative approach for assigning the pumping rates of wells that are located off cell centers. This approach consists of assigning the pumping rate not only to the cell in which the well is located but also to adjacent cells, taking into account the length of the well screen, the hydraulic conductivity, and the distance from the well to the center of its cell. The advantage of this alternative approach over the conventional one is illustrated with a test problem of a synthetic aquifer. Statistical measures of error indicate a much better model fit when pumping rates of wells are distributed over several cells.
Hydrogeologic unit flow characterization using transition probability geostatistics
Authors: Jones Norman L. , Walker Justin R. , Carle Steven F.
Published: May 2006

This paper describes a technique for applying the transition probability geostatistics method for stochastic simulation to a MODFLOW model. Transition probability geostatistics has some advantages over traditional indicator kriging methods including a simpler and more intuitive framework for interpreting geologic relationships and the ability to simulate juxtapositional tendencies such as fining upward sequences. The indicator arrays generated by the transition probability simulation are converted to layer elevation and thickness arrays for use with the new Hydrogeologic Unit Flow package in MODFLOW 2000. This makes it possible to preserve complex heterogeneity while using reasonably sized grids and/or grids with nonuniform cell thicknesses.
High‐resolution slug testing
Authors: Zemansky G.M. , McElwee C.D.
Published: May 2006

The hydraulic conductivity (K) variation has important ramifications for ground water flow and the transport of contaminants in ground water. The delineation of the nature of that variation can be critical to complete characterization of a site and the planning of effective and efficient remedial measures. Site‐specific features (such as high‐conductivity zones) need to be quantified. Our alluvial field site in the Kansas River valley exhibits spatial variability, very high conductivities, and nonlinear behavior for slug tests in the sand and gravel aquifer. High‐resolution, multilevel slug tests have been performed in a number of wells that are fully screened. A general nonlinear model based on the Navier‐Stokes equation, nonlinear frictional loss, non‐Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been used to analyze the data, employing an automated processing system that runs within the Excel spreadsheet program. It is concluded that slug tests can provide the necessary data to identify the nature of both horizontal and vertical K variation in an aquifer and that improved delineation or higher resolution of K structure is possible with shorter test intervals. The gradation into zones of higher conductivity is sharper than seen previously, and the maximum conductivity observed is greater than previously measured. However, data from this project indicate that well development, the presence of fines, and the antecedent history of the well are important interrelated factors in regard to slug‐test response and can prevent obtaining consistent results in some cases.
Short term salbutamol ingestion and supramaximal exercise in healthy women
Authors: Le Panse B , Arlettaz A , Portier H , Lecoq A-M , De Ceaurriz J , Collomp K
Published: May 2006

Objective:To test the hypothesis that chronic salbutamol intake improves performance during supramaximal exercise and to estimate the effects of this treatment on body composition, bone mass, and metabolic indices in healthy women.

Methods:Fourteen female volunteers (seven sedentary and seven recreationally trained) performed a 30 second Wingate test with and without salbutamol ingestion (12 mg/day for four weeks) in a random, double blind, crossover design. Blood samples were collected at rest, at the end of the test, and during passive recovery for lactate measurement. Body composition and bone mass were determined by dual energyxray absorptiometry.

Results:Peak power appeared significantly earlier and was significantly (p<0.05) increased after salbutamol intake in all subjects. There was no difference in total work performed and fatigue indices with salbutamol compared with placebo. No significant alterations in lean or fat body mass and bone variables were observed with salbutamol treatment in either trained or untrained subjects during the trial. In contrast, blood lactate was significantly (p<0.05) increased during the recovery period after salbutamol ingestion compared with placebo.

Conclusion:As in men, chronic administration of therapeutic concentrations of salbutamol did not induce an anabolic effect in women but increased maximal anaerobic power. Further studies are necessary to clarify the mechanisms involved.
Effect of aging on the stride pattern of veteran marathon runners
Authors: Conoboy P , Dyson R
Published: May 2006

Objective:To investigate the stride pattern of different age groups of veteran runners in a marathon road race.

Methods:This kinematic study investigated the stride pattern (stride length, stride period, velocity, stance time, and non-stance time) for 151 runners (78 men aged up to 75–80, 73 women aged up to 60–64) at the 7 mile point.

Results:Significant declines for men with aging were found for mean stride length (from 2.4 m at age 40–49 to 2.0 m at age 60+), velocity, and non-stance time (p<0.05), whereas stride period changed little. The findings indicate that the lower velocities of older runners are associated with shorter strides whereas cadence changes little. However, when a statistical adjustment was made for the variation in runners’ velocity, it was found that older runners did not have a significantly shorter stride length at any given velocity.

Conclusion:Although a shorter stride is the mechanical route by which older runners lose velocity, the shorter stride may not be the fundamental cause of the velocity reduction with age. This has implications for researchers and coaches when investigating and training veteran distance runners.
High-Resolution Multitransistor Array Recording of Electrical Field Potentials in Cultured Brain Slices
Authors: Hutzler M. , Lambacher A. , Eversmann B. , Jenkner M. , Thewes R. , Fromherz P.
Published: May 2006

We report on the recording of electrical activity in cultured hippocampal slices by a multitransistor array (MTA) with 16,384 elements. Time-resolved imaging is achieved with a resolution of 7.8 μm on an area of 1 mm2 at 2 kHz. A read-out of fewer elements allows an enhanced time resolution. Individual transistor signals are caused by local evoked field potentials. They agree with micropipette measurements in amplitude and shape. The spatial continuity of the records provides time-resolved images of evoked field potentials and allows the detection of functional correlations over large distances. As examples, fast propagating waves of presynaptic action potentials are recorded as well as patterns of excitatory postsynaptic potentials across and along cornu ammonis.
Improvement of Phase Information at Low Sound Frequency in Nucleus Magnocellularis of the Chicken
Authors: Fukui Iwao , Sato Tatsuo , Ohmori Harunori
Published: May 2006

Nucleus magnocellularis (NM) is one of the subnuclei of the avian cochlear nucleus and has a role of extracting the temporal information of sound from the auditory nerve fibers (ANFs). Neurons in NM are varied along the tonotopic axis in synaptic transmission and membrane excitability and are high-fidelity relay neurons at the high to middle characteristic frequency (CF) regions. Here we have compared the firing properties between ANFs and NM neurons in vivo and found that at high but not near threshold intensities, spike firings are more phase-locked in NM than in ANFs in the CF region <500 Hz. Moreover, NM shows reduced occurrence of multiple spikes within one cycle of sound stimuli and higher vector strength than ANF. The improved phase-locked firing nature of NM is discussed in relation to the in vitro findings of small EPSCs in the low CF neurons ( Fukui and Ohmori 2004 ). It is concluded that NM neurons are not simple relay neurons in the low CF region but are coincidence detectors of monoaural synaptic inputs that improve the synchronization of spike firing to auditory inputs.
Finite Element Method for Active Vibration Suppression of Smart Composite Structures using Piezoelectric Materials
Authors: Ghasemi-Nejhad Mehrdad N. , Pourjalali Saeid , Uyema Mark , Yousefpour Ali
Published: May 2006

Adaptive or intelligent structures which have the capability for sensing and responding to their environment promise a novel approach to satisfy the stringent performance requirements of future space missions. Analytical, numerical, and experimental results are employed to verify the performance of piezoelectric stacks and patches as well as to determine the natural frequencies of typical strut and panel structures. A strut model with a piezoelectric stack actuator for axial vibration suppression and a composite beam with surface-mounted piezoelectric patch actuator for lateral vibration suppression are considered to model an active composite strut (ACS) and an active composite panel (ACP), respectively. These ACS and ACP are employed to develop an actuator optimum voltage (OV) for active vibration suppression using modal, harmonic, and transient finite element analyses for a range of frequency encompassing a natural frequency. The ACP model demonstrates that the actuator vibration suppression capability depends on the modal shape and location of the actuator. The OV, in this work, is determined by increasing the level of actuator voltage gradually and generating a vibration with same frequencies as the external vibration but 180 out-of-phase, and observing the increasing level of active vibration suppression until an optimum/threshold actuator voltage is reached. Beyond the optimum voltage level, the actuator increased the level of vibration 180 out-of-phase. Modal, harmonic, and transient finite element analyses are performed to verify the results. Selected axial and lateral vibration suppression experiments are also performed to verify the numerical results. The analytical, numerical, and experimental results obtained in this work are in excellent agreements. This work also presents a systematic guideline for the use of piezoelectric stack and monolithic patch smart materials in intelligent structures using the finite element method.
Re-producing pop
Authors: Luvaas Brent
Published: May 2006

Electroclash is an electronic dance music popular in cities like New York, Los Angeles, and London between 2001 and 2004. In this article, I use the example of electroclash to demonstrate the significance of media in structuring social reality. I argue that electroclash constitutes a set of aesthetic tactics for living through the confusions and contradictions of life in a media-saturated, increasingly globalized, late capitalist economy. It is produced by a diverse assemblage of urban youth, whose primary commonality is an ambivalent relationship towards media. Electroclash artists, I argue, engage with and respond to meanings within existing media texts. They ironically perform the clichés and representations of popular culture, re-investing them with critical, though often ambiguous new meanings. In these re-readings of media, I conclude, electroclash artists blur the distinction between celebration and critique, and ultimately complicate any clear-cut, theoretical opposition between resistance and accommodation.
Trans-boundary spaces: Scottish Pakistanis and trans-local/national identities
Authors: Qureshi Karen
Published: May 2006

The analysis presented here is based on ethnographic research spanning approximately four years, and is concerned with the negotiation of identities and belonging(s) among young ‘Scottish Pakistanis’ in Edinburgh. It demonstrates how various forms of physical, mediated and virtual mobility are tied up in both the performative maintenance and reflexive review of identities. Furthermore, it indicates how ‘diverse mobilities’ construct trans-boundary communicative spaces where meanings of identities are exchanged, reflexively debated and played with.
Outcome following patent ductus arteriosus ligation in premature infants: a retrospective cohort analysis
Authors: Lee LLeona CL , Tillett Angela , Tulloh Robert , Yates Robert , Kelsall Wilf
Published: May 2006

Background

The patent ductus arteriosus (PDA) is an important problem in premature infants. Surgical PDA ligation is usually only be considered when medical treatment has either failed or was contraindicated. The aims of our study were to determine the mortality and morbidity following patent ductus arteriosus ligation in premature infants, and whether prostaglandin synthetase inhibitor (PSI) use prior to ligation affects outcome.

Methods

A retrospective case note review study to determine the outcome of premature infants undergoing patent ductus arteriosus ligation in one tertiary neonatal intensive care unit and two paediatric cardiothoracic centres.

Results

We had follow-up data on 87 infants. Cumulative mortality rates at 7 days, 30 days and at hospital discharge were 2%, 8% and 20% respectively. The incidence of chronic lung disease, intraventricular haemorrhage, necrotising enterocolitis and retinopathy of prematurity were 77%, 39%, 26% and 28% respectively. There was no difference in mortality, incidence of chronic lung disease or duration of oxygen dependence between those who had and those who had not received a PSI prior to surgical ligation. In those who had received 2 or more courses of PSI prior to surgical ligation, there was a trend to increase in the duration of oxygen therapy and chronic lung disease, but no difference in mortality.

Conclusion

This study shows that patent ductus arteriosus ligation is a relatively safe procedure (30 day survival 92%) but there is substantial late mortality and a high incidence of morbidity in the survivors. 2 or more courses of PSI prior to surgical ligation trends to increased oxygen dependence and chronic lung disease. This high risk population requires careful follow-up. A definitive prospective cohort study is lacking.
New Canadian natural health product regulations: a qualitative study of how CAM practitioners perceive they will be impacted
Authors: Moss Karen , Boon Heather , Ballantyne Peri , Kachan Natasha
Published: May 2006

Background

New Canadian policy to regulate natural health products (NHPs), such as herbs and vitamins were implemented on January 1st, 2004. We explored complementary and alternative medicine (CAM) practitioners' perceptions of how the new regulations may affect their practices and relationships with patients/consumers.

Methods

This was an applied ethnographic study. Data were collected in fall 2004 via qualitative interviews with 37 Canadian leaders of four CAM groups that use natural products as a core part of their practises: naturopathic medicine, traditional Chinese medicine (TCM), homeopathic medicine and Western herbalism. All interviews were transcribed verbatim and coded independently by a minimum of two investigators using content analysis.

Results

Three key findings emerged from the data: 1) all CAM leaders were concerned with issues of their own access to NHPs; 2) all the CAM leaders, except for the homeopathic leaders, specifically indicated a desire to have a restricted schedule of NHPs; and 3) only naturopathic leaders were concerned the NHP regulations could potentially endanger patients if they self-medicate incorrectly.

Conclusion

Naturopaths, TCM practitioners, homeopaths, and Western herbalists were all concerned about how the new NHP regulations will affect their access to the products they need to practice effectively. Additional research will need to focus on what impacts actually occur as the regulations are implemented more fully.
Control of muscle regeneration in theXenopustadpole tail by Pax7
Authors: Chen Ying , Lin Gufa , Slack Jonathan M. W.
Published: May 2006

The tail of the Xenopus tadpole will regenerate completely after transection. Much of the mass of the regenerate is composed of skeletal muscle, but there has been some uncertainty about the source of the new myofibres. Here, we show that the growing tail contains many muscle satellite cells. They are active in DNA replication, whereas the myonuclei are not. As in mammals, the satellite cells express pax7. We show that a domain-swapped construct, pax7EnR, can antagonize pax7function. Transgenic tadpoles were prepared containing pax7EnR driven by a heat-inducible promoter. When induced, this reduces the proportion of satellite cells formed in the regenerate. A second amputation of the resulting tails yielded second regenerates containing notochord and spinal cord but little or no muscle. This shows that inhibition of pax7 action does not prevent differentiation of satellite cells to myofibres, but it does prevent their maintenance as a stem cell population.
Separating the adhesive and signaling functions of the Fat and Dachsous protocadherins
Authors: Matakatsu Hitoshi , Blair Seth S.
Published: May 2006

The protocadherins Fat (Ft) and Dachsous (Ds) are required for several processes in the development of Drosophila, including controlling growth of imaginal discs, planar cell polarity (PCP) and the proximodistal patterning of appendages. Ft and Ds bind in a preferentially heterophilic fashion, and Ds is expressed in distinct patterns along the axes of polarity. It has thus been suggested that Ft and Ds serve not as adhesion molecules, but as receptor and ligand in a poorly understood signaling pathway. To test this hypothesis, we performed a structure-function analysis of Ft and Ds,separating their adhesive and signaling functions. We found that the extracellular domain of Ft is not required for its activity in growth, PCP and proximodistal patterning. Thus, ligand binding is not necessary for Ft activity. By contrast, the extracellular domain of Ds is necessary and sufficient to mediate its effects on PCP, consistent with the model that Ds acts as a ligand during PCP. However, we also provide evidence that Ds can regulate growth independently of Ft, and that the intracellular domain of Ds can affect proximodistal patterning, both suggestive of functions independent of binding Ft. Finally, we show that ft mutants or a dominant-negative Ft construct can affect disc growth without changes in the expression of wingless and Wingless target genes.
A Facile Synthesis of 3-Deoxy-α-D-manno-2-octulopyranosides Using Pyridinium p-Toluenesulfonate
Authors: Horito Shigeomi , Tada Muneo , Hashimoto Hironobu
Published: May 2006

A new method of ketosidation was developed using 4,5:7,8-di-O-isopropylidenated 3-deoxy-D-manno-2-octulose and its 1-O-protected derivatives as ketosyl donors in the presence of pyridinium p-toluenesulfonate to afford the α-ketoside exclusively.
Oligoribonucleotide Synthesis By Use of the [[2-(Methylthio)phenyl]thio]methyl (MPTM) Group as the 2′-Hydroxyl Protecting Group
Authors: Sekine Mitsuo , Nakanishi Takashi
Published: May 2006

A new 2′-hydroxyl protecting group, [[2-(methylthio)phenyl]thio]methyl (MPTM), was introduced via a three-step reaction into the 2′-position of uridine and cytidine units required for the synthesis of oligoribonucleotides in the phosphotriester approach. By using these monomer building blocks, CpUpG was synthesized.
Asymmetric Reductions with Freely and Non-freely Rotating Amide Group NADH Models
Authors: Combret Yves , Torche Jean Jacques , Binay Patrice , Dupas Georges , Bourguignon Jean , Queguiner Guy
Published: May 2006

NADH models with a freely or non freely rotating chiral amide group have been synthesized and used in the reduction of methyl benzoylformate. The same major enantiomer was obtained in all cases. A blocked reagent bearing a phenylalaninol group as chiral auxiliary allows one to obtain a high e.e.
Photochemical Reactions of 4-Methyl-2-quinolinecarbonitrile with Optically Active 2-Phenylpropionic Acids. The Magnetic-Field and Solvent Effects
Authors: Hata Norisuke
Published: May 2006

The photochemical reactions of 4-methyl-2-quinolinecarbonitrile with (S)- or (R)-2-phenylpropionic acid (PPCOOH) in benzene were investigated in the absence and in the presence of a magnetic field. The reactions were also examined in polar solvents such as dichloromethane and acetonitrile. The experimental results led to the conclusion that (S)- and (R)-forms of the 2-phenylpropionate ion () differ distinctly in their chemical properties.
Synthesis of Optically Active Selenonium Ylide
Authors: Kamigata Nobumasa , Nakamura Yoshihiro , Matsuyama Haruo , Shimizu Toshio
Published: May 2006

Fractional recrystallization of diastereomeric methyl[4′-(l-menthyloxycarbonyl)phenyl]selenonium 4,4-dimethyl-2,6-dioxocyclohexylide from hexane-ether gave optically pure (+)-selenonium ylide as a stable crystal.
Preparation of SiO2–ZrO2–Na2O Porous Glasses
Authors: Tsurita Yasushi , Wada Keisuke
Published: May 2006

A new method for preparation of porous supports was investigated through heating the sol-gel derived SiO2–ZrO2 microspherical gel in the presence of NaCl. The products were composed of sponge-like structure similar to the porous glasses manufactured by the phase separation method.
The Liquid-Phase Photolyses of Tetra- and Octa-CDDs and Their CDFs in Hexane Solution
Authors: Muto Hajime , Takizawa Yukio
Published: May 2006

The liquid phase photolyses were conducted with a hexane solution of tetra- and octa-CDD and their CDFs at 254 nm. Their first-order rate constants obtained were as follows(× 10−5 s−1): 2,3,7,8-TCDD, 29.2; 1,2,3,4-TCDD, 13.1; 2,3,7,8-TCDF, 46.0; octa-CDD, 17.7. The PCDF photolyses of 2,3,7,8-tetra- and octa-congeners compared to their CDDs were more rapidly, as well as the photodestructions of 2,3,7,8-chlorine substituted DD and DF which are more highly toxic substances.
Oxygenation of Silyl Enol Ethers and Silyl Ketene Acetals with Molecular Oxygen and Aldehyde Catalyzed by Nickel(II) Complex. A Convenient Method for the Preparation of α-Hydroxy Carbonyl Compounds
Authors: Takai Toshihiro , Yamada Tohru , Rhode Oliver , Mukaiyama Teruaki
Published: May 2006

In the presence of a catalytic amount of nickel(II) complex, silyl enol ethers and silyl ketene acetals are smoothly oxygenated by the combined use of molecular oxygen and aldehyde to afford α-siloxy carbonyl compounds via possible intermediates, siloxy epoxides. And on treatment of the α-siloxy carbonyl compounds with potassium fluoride α-hydroxy carbonyl compounds are obtained in good to high yields.
ESR Microscopic Imaging on the Spatial Distribution of Paramagnetic Reactive Centers on Catalysts
Authors: Xu Yuanzhi , Furusawa Masahiro , Ikeya Motoji , Kera Yoshiya , Kuwata Keiji
Published: May 2006

An ESR microscopic imaging on the V4+ and Mo5+ ions Dispersed in the tablets of silica and zeolite carriers was carried out. Distributions of these ions on the surfaces and the cross sections of the catalyst tablets were observed. These results may be a useful information about proper shapes, sizes, and operating conditions of the catalyst particles.
Visible Light-Assisted Dehydrogenation of Alkanes Catalyzed by the RhCl(CH2=CH2)(PMe3)2-hν System
Authors: Sakakura Toshiyasu , Abe Fujio , Tanaka Masato
Published: May 2006

Alkanes are catalytically dehydrogenated to alkenes with RhCl(CH2=CH2)(PMe3)2 (λmax 416 nm) under visible light irradiation in the presence of ethylene. The reaction proceeds smoothly even at room temperature; the quantum yield of cyclooctane dehydrogenation was 0. 10 at 25 °C.
Characteristic Reduction of Ketones by Bu3SnH–Bu4NX System
Authors: Shibata Ikuya , Yoshida Tomoyuki , Baba Akio , Matsuda Haruo
Published: May 2006

Various ketones were reduced cleanly by Bu3SnH–Bu4NX (X = halogen) combined systems. The reaction proceeds effectively under mild conditions. Chemoselective reduction was performed in bifunctional compounds, and marked diastereoselective reduction was noted for α-methoxy propiophenone.
Gate Function of Viologen Monolayer Adsorbed on Mercury Electrode for Some Redox–Electrode Reactions
Authors: Kitamura Fusao , Ohsaka Takeo , Tokuda Koichi
Published: May 2006

The progress of electron exchange between 4-hydroxy-2,2,6,6-tetramethyl-piperidinyl-1-oxy (TEMPOL) and a hanging mercury drop electrode can be controlled by changing the oxidation state of monolayer of 1,1′-diheptyl-4,4′-bipyridinium dication (heptyl viologen) adsorbed on the electrode; the monolayer is “open” in the oxidized state and “closed” in the reduced state.
A Novel Approach to the Determination of Trace α-Amylase by Photographic Assay. The Synthesis and Enzymatic Characterization of an Oligosaccharide Derivative as a Substrate for α- Amylase from Porcine Pancreas
Authors: Ono Mitsunori , Suzuki Nobuo , Hirano Shigeo , Itoh Isamu , Masuda Nobuhito
Published: May 2006

In line with a new concept for the photographic assay on the basis of chemical amplification by the catalytic Ag° nuclei, an α-amylase substrate containing a new sensitive labeling component and a bioaffinity group was designed and synthesized. The analysis of enzymatic degradation proved that the substrate can release efficiently the labeling component without loss of photographic activity.
Novel Conversion of N,N-Dimethylformamide Dimethyl Acetal to Tetramethylammonium Salts by Its Reaction with 5-Methyl-4-Isoxazolecarboxylic Acid Derivatives
Authors: Singh Baldev , Hlavac Allan G
Published: May 2006

N,N-Dimethylformamide dimethyl acetal is converted to tetramethylammonium salts upon treatment with 5-methyl-4-isoxazolecarboxylic acid derivatives.
Photoreduction of Solid Europium Chloride in KBr by Visible Two-photon Excitation
Authors: Yamada Yasuhiro , Ohno Shin-ichi
Published: May 2006

Solid EuCl3·6H2O in KBr disk was irradiated by visible laser light ranging from 455 nm to 475 nm condensed by lens and the time-resolved emission spectra were measured. Reduction of Eu3+ and emission from Eu2+ were observed by simultaneous two-photon absorption in solid sample.
Novel Asymmetric Synthesis of γ-Alkylated Lactones via Successive Alkylation and Reduction of Chiral Cyclic Imides with C2-Symmetry
Authors: Yoda Hidemi , Shirakawa Koji , Takabe Kunihiko
Published: May 2006

Consecutive treatment of chiral cyclic imides containing a C2-axis of symmetry with Grignard reagents and sodium borohydride followed by cyclization furnished γ-alkylated lactones with high diastereoselectivity. Products were converted to synthetically useful R-butenolides after removal of the chirality inducing groups.
Generation of Cation Radicals from Allylic Sulfides and Their Reactions with Silyl Enol Ethers by the Use of Cerium(IV) Ammonium Nitrate
Authors: Narasaka Koichi , Okauchi Tatsuo
Published: May 2006

Allyl sulfides react with silyl enol ether, siloxy diene and siloxy enyne by the oxidation with cerium(IV) ammonium nitrate to give α-phenylthio γ,δ-unsaturated ketones through the nucleophilic addition of silyl enol ethers to the sulfur cation radicals and the successive [2,3]-sigmatropic rearrangement.