bluuebunny/crossref_metadata_2025 huggingface dataset:
Cleavage of proBDNF by tPA/Plasmin Is Essential for Long-Term Hippocampal Plasticity
Authors: Pang Petti T. , Teng Henry K. , Zaitsev Eugene , Woo Newton T. , Sakata Kazuko , Zhen Shushuang , Teng Kenneth K. , Yung Wing-Ho , Hempstead Barbara L. , Lu Bai
Published: October 2004

Long-term memory is thought to be mediated by protein synthesis–dependent, late-phase long-term potentiation (L-LTP). Two secretory proteins, tissue plasminogen activator (tPA) and brain-derived neurotrophic factor (BDNF), have been implicated in this process, but their relationship is unclear. Here we report that tPA, by activating the extracellular protease plasmin, converts the precursor proBDNF to the mature BDNF (mBDNF), and that such conversion is critical for L-LTP expression in mouse hippocampus. Moreover, application of mBDNF is sufficient to rescue L-LTP when protein synthesis is inhibited, which suggests that mBDNF is a key protein synthesis product for L-LTP expression.
The Role of the Medial Frontal Cortex in Cognitive Control
Authors: Ridderinkhof K. Richard , Ullsperger Markus , Crone Eveline A. , Nieuwenhuis Sander
Published: October 2004

Adaptive goal-directed behavior involves monitoring of ongoing actions and performance outcomes, and subsequent adjustments of behavior and learning. We evaluate new findings in cognitive neuroscience concerning cortical interactions that subserve the recruitment and implementation of such cognitive control. A review of primate and human studies, along with a meta-analysis of the human functional neuroimaging literature, suggest that the detection of unfavorable outcomes, response errors, response conflict, and decision uncertainty elicits largely overlapping clusters of activation foci in an extensive part of the posterior medial frontal cortex (pMFC). A direct link is delineated between activity in this area and subsequent adjustments in performance. Emerging evidence points to functional interactions between the pMFC and the lateral prefrontal cortex (LPFC), so that monitoring-related pMFC activity serves as a signal that engages regulatory processes in the LPFC to implement performance adjustments.
Separate Neural Systems Value Immediate and Delayed Monetary Rewards
Authors: McClure Samuel M. , Laibson David I. , Loewenstein George , Cohen Jonathan D.
Published: October 2004

When humans are offered the choice between rewards available at different points in time, the relative values of the options are discounted according to their expected delays until delivery. Using functional magnetic resonance imaging, we examined the neural correlates of time discounting while subjects made a series of choices between monetary reward options that varied by delay to delivery. We demonstrate that two separate systems are involved in such decisions. Parts of the limbic system associated with the midbrain dopamine system, including paralimbic cortex, are preferentially activated by decisions involving immediately available rewards. In contrast, regions of the lateral prefrontal cortex and posterior parietal cortex are engaged uniformly by intertemporal choices irrespective of delay. Furthermore, the relative engagement of the two systems is directly associated with subjects' choices, with greater relative fronto-parietal activity when subjects choose longer term options.
Molecular Architecture of the KvAP Voltage-Dependent K
+
Channel in a Lipid Bilayer
Authors: Cuello Luis G. , Cortes D. Marien , Perozo Eduardo
Published: October 2004

We have analyzed the local structure and dynamics of the prokaryotic voltage-dependent K
+
channel (KvAP) at 0 millivolts, using site-directed spin labeling and electron paramagnetic resonance spectroscopy. We show that the S4 segment is located at the protein/lipid interface, with most of its charges protected from the lipid environment. Structurally, S4 is highly dynamic and is separated into two short helices by a flexible linker. Accessibility and dynamics data indicate that the S1 segment is surrounded by other parts of the protein. We propose that S1 is at the contact interface between the voltage-sensing and pore domains. These results establish the general principles of voltage-dependent channel structure in a biological membrane.
Stable Low-Pressure Hydrogen Clusters Stored in a Binary Clathrate Hydrate
Authors: Florusse Louw J. , Peters Cor J. , Schoonman Joop , Hester Keith C. , Koh Carolyn A. , Dec Steven F. , Marsh Kenneth N. , Sloan E. Dendy
Published: October 2004

Thermodynamic, x-ray diffraction, and Raman and nuclear magnetic resonance spectroscopy measurements show that clusters of H
2
can be stabilized and stored at low pressures in a sII binary clathrate hydrate. Clusters of H
2
molecules occupy small water cages, whereas large water cages are singly occupied by tetrahydrofuran. The presence of this second guest component stabilizes the clathrate at pressures of 5 megapascals at 279.6 kelvin, versus 300 megapascals at 280 kelvin for pure H
2
hydrate.
A Bayesian Truth Serum for Subjective Data
Authors: Prelec Dražen
Published: October 2004

Subjective judgments, an essential information source for science and policy, are problematic because there are no public criteria for assessing judgmental truthfulness. I present a scoring method for eliciting truthful subjective data in situations where objective truth is unknowable. The method assigns high scores not to the most common answers but to the answers that are more common than collectively predicted, with predictions drawn from the same population. This simple adjustment in the scoring criterion removes all bias in favor of consensus: Truthful answers maximize expected score even for respondents who believe that their answer represents a minority view.
Exact and Approximate Arithmetic in an Amazonian Indigene Group
Authors: Pica Pierre , Lemer Cathy , Izard Véronique , Dehaene Stanislas
Published: October 2004

Is calculation possible without language? Or is the human ability for arithmetic dependent on the language faculty? To clarify the relation between language and arithmetic, we studied numerical cognition in speakers of Mundurukú, an Amazonian language with a very small lexicon of number words. Although the Mundurukú lack words for numbers beyond 5, they are able to compare and add large approximate numbers that are far beyond their naming range. However, they fail in exact arithmetic with numbers larger than 4 or 5. Our results imply a distinction between a nonverbal system of number approximation and a language-based counting system for exact number and arithmetic.
Science Weighs In on the Scales of Justice
Authors: Kevles Bettyann Holtzmann
Published: October 2004

Laws of Men and Laws of Nature
The History of Scientific Expert Testimony in England and America. by Tal Golan. Harvard University Press, Cambridge, MA, 2004. 335 pp. $49.95, £32.95, €46.10. ISBN 0-674-01286-0.

Laboratory of Justice
The Supreme Court's 200-Year Struggle to Integrate Science and the Law. David L. Faigman. Times Books, New York, 2004. 432 pp. $27.50, C$41.95. ISBN 0-8050-7274-8.

In these two thoughtful histories of the fitful relationship between science and the law, Golan focus on trials where the legal battles began and Faigman on the arena where a select few were concluded.
arrA
Is a Reliable Marker for As(V) Respiration
Authors: Malasarn D. , Saltikov C. W. , Campbell K. M. , Santini J. M. , Hering J. G. , Newman D. K.
Published: October 2004

Arsenate [As(V)]-respiring bacteria affect the speciation and mobilization of arsenic in the environment. This can lead to arsenic contamination of drinking water supplies and deleterious consequences for human health. Using molecular genetics, we show that the functional gene for As(V) respiration,
arrA
, is highly conserved; that it is required for As(V) reduction to arsenite when arsenic is sorbed onto iron minerals; and that it can be used to identify the presence and activity of As(V)-respiring bacteria in arsenic-contaminated iron-rich sediments. The expression of
arrA
thus can be used to monitor sites in which As(V)-respiring bacteria may be controlling arsenic geochemistry.
Neuroeconomics: The Consilience of Brain and Decision
Authors: Glimcher Paul W. , Rustichini Aldo
Published: October 2004

Economics, psychology, and neuroscience are converging today into a single, unified discipline with the ultimate aim of providing a single, general theory of human behavior. This is the emerging field of neuroeconomics in which consilience, the accordance of two or more inductions drawn from different groups of phenomena, seems to be operating. Economists and psychologists are providing rich conceptual tools for understanding and modeling behavior, while neurobiologists provide tools for the study of mechanism. The goal of this discipline is thus to understand the processes that connect sensation and action by revealing the neurobiological mechanisms by which decisions are made. This review describes recent developments in neuroeconomics from both behavioral and biological perspectives.
Endoplasmic Reticulum Stress Links Obesity, Insulin Action, and Type 2 Diabetes
Authors: Özcan Umut , Cao Qiong , Yilmaz Erkan , Lee Ann-Hwee , Iwakoshi Neal N. , Özdelen Esra , Tuncman Gürol , Görgün Cem , Glimcher Laurie H. , Hotamisligil Gökhan S.
Published: October 2004

Obesity contributes to the development of type 2 diabetes, but the underlying mechanisms are poorly understood. Using cell culture and mouse models, we show that obesity causes endoplasmic reticulum (ER) stress. This stress in turn leads to suppression of insulin receptor signaling through hyperactivation of c-Jun N-terminal kinase (JNK) and subsequent serine phosphorylation of insulin receptor substrate–1 (IRS-1). Mice deficient in X-box–binding protein–1 (XBP-1), a transcription factor that modulates the ER stress response, develop insulin resistance. These findings demonstrate that ER stress is a central feature of peripheral insulin resistance and type 2 diabetes at the molecular, cellular, and organismal levels. Pharmacologic manipulation of this pathway may offer novel opportunities for treating these common diseases.
Mass Spectrometry Sampling Under Ambient Conditions with Desorption Electrospray Ionization
Authors: Takáts Zoltán , Wiseman Justin M. , Gologan Bogdan , Cooks R. Graham
Published: October 2004

A new method of desorption ionization is described and applied to the ionization of various compounds, including peptides and proteins present on metal, polymer, and mineral surfaces. Desorption electrospray ionization (DESI) is carried out by directing electrosprayed charged droplets and ions of solvent onto the surface to be analyzed. The impact of the charged particles on the surface produces gaseous ions of material originally present on the surface. The resulting mass spectra are similar to normal ESI mass spectra in that they show mainly singly or multiply charged molecular ions of the analytes. The DESI phenomenon was observed both in the case of conductive and insulator surfaces and for compounds ranging from nonpolar small molecules such as lycopene, the alkaloid coniceine, and small drugs, through polar compounds such as peptides and proteins. Changes in the solution that is sprayed can be used to selectively ionize particular compounds, including those in biological matrices. In vivo analysis is demonstrated.
Lessons from Primates
Authors: Dolins Francine
Published: October 2004

Intelligence of Apes and Other Rational Beings
. Duane M. Rumbaugh and David A. Washburn. Yale University Press, New Haven, CT, 2003. 344 pp. $37.50, £29. ISBN 0-300-09983-5. Current Perspectives in Psychology.

The authors present a framework they call rational behaviorism to explore what apes and monkeys know and how we know that.
Language and the Origin of Numerical Concepts
Authors: Gelman Rochel , Gallistel C. R.
Published: October 2004

Reports of research with the Pirahã and Mundurukú Amazonian Indians of Brazil lend themselves to discussions of the role of language in the origin of numerical concepts. The research findings indicate that, whether or not humans have an extensive counting list, they share with nonverbal animals a language-independent representation of number, with limited, scale-invariant precision. What causal role, then, does knowledge of the language of counting serve? We consider the strong Whorfian proposal, that of linguistic determinism; the weak Whorfian hypothesis, that language influences how we think; and that the “language of thought” maps to spoken language or symbol systems.
Familial risk of urinary incontinence in women: population based cross sectional study
Authors: Hannestad Yngvild S , Lie Rolv Terje , Rortveit Guri , Hunskaar Steinar
Published: October 2004

Objective
To determine whether there is an increased risk of urinary incontinence in daughters and sisters of incontinent women.

Design
Population based cross sectional study.

Setting
EPINCONT (the epidemiology of incontinence in the county of Nord-Trøndelag study), a substudy of HUNT 2 (the Norwegian Nord-Trøndelag health survey 2), 1995-7.

Participants
6021 mothers, 7629 daughters, 332 granddaughters, and 2104 older sisters of 2426 sisters.

Main outcome measures
Adjusted relative risks for urinary incontinence.

Results
The daughters of mothers with urinary incontinence had an increased risk for urinary incontinence (1.3, 95% confidence interval 1.2 to 1.4; absolute risk 23.3%), stress incontinence (1.5, 1.3 to 1.8; 14.6%), mixed incontinence (1.6, 1.2 to 2.0; 8.3%), and urge incontinence (1.8, 0.8 to 3.9; 2.6%). If mothers had severe symptoms then their daughters were likely to have such symptoms (1.9, 1.3 to 3.0; 4.0%). The younger sisters of female siblings with urinary incontinence, stress incontinence, or mixed incontinence had increased relative risks of, respectively, 1.6 (1.3 to 1.9; absolute risk 29.6%), 1.8 (1.3 to 2.3; 18.3%), and 1.7 (1.1 to 2.8; 10.8%).

Conclusion
Women are more likely to develop urinary incontinence if their mother or older sisters are incontinent.
Introduction of nurse led DC cardioversion service in day surgery unit: prospective audit
Authors: Currie M P , Karwatowski S P , Perera J , Langford E J
Published: October 2004

Problem
Atrial fibrillation is the most common persistent arrhythmia in adults and carries an increased risk of thromboembolism and stroke. Electrical (DC) cardioversion is an effective treatment, but logistical difficulties in many institutions lead to problems providing a prompt service. This reduces the rate of long term success, delays relief of symptoms, and increases the burden on anticoagulation clinics.

Design
Prospective audit of introduction of a collaborative, nurse led DC cardioversion service in a day surgery unit.

Setting
Day surgery unit 5 km from an acute hospital in southeast London.

Key measures for improvement
Waiting times, success of procedures, and complication rates.

Strategies for change
Collaborative working across traditional specialty boundaries; empowerment of patients within the process; using a nurse consultant as a single point of reference to coordinate the service.

Effects of change
Sinus rhythm was restored in 131 (92%) of the first 143 patients treated. Three patients needed hospital admission; all were discharged uneventfully within 24 hours. No important complications occurred. Waiting times were reduced from 27 weeks to eight weeks for patients eligible for the service.

Lessons learnt
Elective DC cardioversion under general anaesthesia can be safely done by an appropriately trained nurse in a day surgery unit remote from an acute general hospital. This model of care is effective and can reduce waiting times and relieve pressure on acute beds and junior doctors.
Flow regimes and structure in pool and weir fishways
Authors: Ead S A , Katopodis C , Sikora G J , Rajaratnam N
Published: October 2004

The main objective of this work was to study the hydraulics of pool and weir fishways, for wider range of bed slopes, weir spacing, and heights, so that they can be designed to allow the passage of different species and sizes of fish. This laboratory study contains the results of 435 experiments, including the flow regimes, main flow characteristics and velocity profiles for several discharges. The flow regimes may be classified into plunging, transitional, streaming, and supercritical jet flows. A diagram has been developed to predict the different flow regimes using two dimensionless variables, Qt* and L/p. The dimensionless discharge Q+ for plunging flows was found to follow the Rehbock equation while Q* assumed a constant value equal to 5.75 for streaming flows. Velocity profiles in plunging as well as in streaming flows were found to be similar and correlations have been developed for the velocity and length scales. If the present work is considered to be a scale-model study, the scale would be approximately 10. Key words: fishways, pools and weirs, hydraulics, turbulent flow, energy dissipation, fisheries management.
New portable fishway design for existing trapezoidal weirs
Authors: Yasuda Youichi , Ohtsu Iwao , Takahashi Masuyuki
Published: October 2004

The improvement of the weir without a fishway is required in order that diadromous fishes, shrimps, and crabs can migrate to their upstream and downstream habitats. This paper presents a proposal of a portable fishway to be set on the waterside of a trapezoidal weir and discusses the effect of the proposed fishway on the migration of diadromous aquatic animals in the trapezoidal weir. Field experiments concerning the proposed fishway were carried out at a trapezoidal weir having a slope of 26.5° (Vertical 1: Horizontal 2) and 2.0 m drop height. The field experiments revealed that the juvenile ayu fish (Plecoglossus altivelis) having a body length of 4.4–10 cm could migrate to their upstream habitats through the proposed portable fishway even if the slope of the fishway is 19°. About 120 000 juvenile ayu could migrate upstream via the fishway during 9 d. The migration route of juvenile ayu can be explained on the basis of the flow characteristics in the fishway. Measurements of the flow velocity and the air concentration distribution in the portable fishway support the conclusion that the juvenile ayu can easily migrate upstream through the fishway. Also, the proposed fishway could be helpful for the upstream migration of benthic fishes, shrimps, and crabs. Key words: fishway, migration, diadromous fish, gabion, drop structure, weir.
Electrolytic treatment of azo dyes containing o,o′-dihydroxyazo complexation sites
Authors: Kupferle Margaret J , Galal Ahmed , Bishop Paul L
Published: October 2004

The impact of structure on decolorization rate was studied for two azo dyes containing the o,o′-dihydroxyazo complexation site, Direct Red 83 and Acid Alizarin Violet N. Both dyes were investigated with and without complexed copper; the methoxylated pre-cursor of Direct Red 83 was also investigated. The dye solutions were electrolytically treated and sample conductivity, pH, and temperature were measured before and after each 60-min run. The UV–VIS absorbance spectra of samples were measured at 10 min intervals with and without quenching of chlorine residuals with sodium thiosulfate. The decolorization rate data calculated from the absorbance spectra were plotted as fraction of dye remaining, Ct/C0, versus time, t, in seconds. First-order curves were fitted to the data, and the apparent first-order rate constant, k, was calculated for each dye. In general, the Acid Alizarin Violet N forms were decolorized more rapidly than the Direct Red 83 forms, the presence of copper protected the dyes from the continuation of indirect oxidation, and methoxylation reduced the first-order rate constant, but it did not protect the azo bond from continued indirect oxidation as was the case with copper. Key words: azo dye, structure, electrolytic treatment, electrochemical, color, decolorization, rate constant.
Evaluation of bacteriological indicators of disinfection for alkaline treated biosolids
Authors: Meckes Mark C , Rhodes Eric R
Published: October 2004

A suite of methods was used to enumerate fecal coliforms, total culturable heterotrophs, Escherichia coli (E. coli), Clostridium perfringens endospores (C. perfringens), aerobic endospores, and Salmonella spp. in untreated municipal sludge and lime treated biosolids. Results of this work indicate that the fecal coliform methods used during this evaluation were not significantly different (α = 0.05). Similarly the E. coli methods were also shown to be not significantly different (α = 0.05). We also found that the fecal coliform and E. coli populations are more susceptible to lime treatment than other heterotrophic bacteria. Endospore forming bacteria were found to survive lime treatment while the numbers of other indicator organisms were significantly reduced. Finally, we showed that the density of aerobic endospores and their resistance to lime treatment was comparable to the densities and resistance of C. perfringens endospores in both Class A and B alkaline treated biosolids. Key words: biosolids, fecal coliform, salmonellae, Escherichia coli, Clostridium perfringens endospores, aerobic endospores, sludge, lime, disinfection.
Removal of dimethyl phthalate from water by UV–H2O2 process
Authors: Tawabini Bassam S , Al-Suwaiyan Mohammed S
Published: October 2004

This study aims to demonstrate the removal efficiency of dimethyl phthalate from water using the UV–H2O2 photooxidation process. Pure water samples, spiked with 20 ppm dimethyl phthalate (DMP) were treated by the combined effect of UV photolysis as well as hydrogen peroxide oxidation mechanisms. In the experiments, the concentration of hydrogen peroxide was varied from 34 to 136 ppm and a low-pressure mercury UV lamp of 100 mW power output was used to provide the necessary radiation. The effects of initial concentration of H2O2, UV exposure time, pH, and temperature were investigated. The results showed that about 60% of DMP were removed directly by activation caused by UV light radiation intensity after an exposure time of 1 h. However, the removal efficiency increased when the DMP-spiked water was dosed with H2O2 prior to irradiating with UV light (i.e., UV–H2O2). More than 98% of DMP was removed after 45 min when the UV-irradiated solution was dosed with 136 ppm of H2O2. The results also showed that lowering the pH and increasing the temperature enhanced the removal of DMP by UV–H2O2 process. Key words: ultraviolet light, hydrogen peroxide, hydroxyl radical, phthalates, UV–H2O2 process, advanced oxidation processes.
Near-bed hydrodynamic measurements above boulders in shallow torrential streams: Implications for stream biota
Authors: Hoover Trent M , Ackerman Josef Daniel
Published: October 2004

The near-bed hydraulic environment inhabited by torrential stream fauna was characterized by recording velocity profiles, near-bed velocities, and local wall shear stresses over the upper surface of boulders (or stones) in a mountain stream located in eastern British Columbia. Velocity profiles regularly deviated from a semi-logarithmic shape, and were often found to be "wedge-shaped", due likely to near-bed acceleration resulting from flow constriction over the leading edge of the stones. Local bed shear stress (τw) measured using a Preston-static tube (PST) was generally lowest over the leading edge of the boulders, and increased over the upper surface, reaching a maximum near the rear of the stone (upstream of the point of flow separation). Local bed shear stresses measured by the PST were similar to those estimated from the law of the wall (i.e., velocity gradient method based on estimating τw from the slope of the regression of U on ln(z)) only at locations where velocity profiles were log-normally distributed. Where velocity profiles were wedge-shaped, the law of the wall underestimated τw compared to the direct measurements using the PST. The possible influences of torrential streambed geometry and relative submergence on near-bed flow parameters and the ecology of stream fauna are discussed. Key words: benthic, velocity profile, shear stress, Preston-static tube, law of the wall, rough turbulent flow.
Understanding air–water mass transfer in rectangular dropshafts
Authors: Chanson H
Published: October 2004

A dropshaft is a vertical structure connecting two channels with different invert elevations. Four configurations of rectangular dropshafts were investigated systematically to study the effects of outflow direction and pool depth on particle residence times and flow aeration. The best hydraulic design was that with 180° outflow direction and deep pool shaft. For that design, a full-scale study was conducted, the scaling ratio between prototype and model being 3.1:1. Although similar trends were seen in both model and prototype, scale effects were observed in terms of particle residence times and bubble swarm depths. In the prototype, detailed air–water flow measurements were performed in the shaft pool and the mass transfer equation was integrated using measured interfacial areas and particle residence times. The results demonstrate that the air–water mass transfer is the largest at low flow rates (regime R1) because of large residence times and significant interfacial area. Overall the present study provides new understanding of the basic mechanisms of air–water mass transfer in rectangular dropshafts. Key words: dropshaft, mass transfer, aeration, hydraulics.
Hydraulic considerations in designing an oil spill control system for a stormwater outfall
Authors: Li James , Chui Jenny
Published: October 2004

Oil spills have been identified to be a serious problem in the Humber Creek subwatershed in Toronto. To capture spilled oil at the storm water outfall, an oil spill control system was designed to perform under different flow conditions. The spill control system consists of an on-line triangular lateral diversion channel (1.7 m by 0.6 m) and an off-line tilted-plate oil–water separator (7 m by 5.4 m by 5.9 m). To investigate the hydraulic behaviour of the spill control system under different flow conditions, a physical model study was conducted at the National Water Research Institute's Hydraulics Laboratory in Burlington, Ontario. The model results confirmed the design conveyance capacity of the lateral diversion channel and indicated that floating objects and settleable solids could be trapped inside the oil–water separator under various flow conditions. A vortex was also observed inside the oil–water separator and was likely caused by the lateral diversion channel. During high flows, the flow through the oil–water separator was controlled by the flow backup from the storm water outfall. Key words: oil spills, lateral channel, oil–water separator, hydraulic models, storm conditions.
Low temperature oxidation for the remediation of soil contaminated with motor oil
Authors: Catalan Lionel JJ , Buset Kathleen C , Kling Laura
Published: October 2004

Petroleum hydrocarbons (PHCs) react with oxygen by low temperature oxidation (LTO) to produce a coke-like solid residue, carbon oxide gases, and vaporized hydrocarbons. The feasibility of using LTO to remediate sandy soil contaminated with motor oil has been investigated in a plug flow reactor operated at temperatures between 150 and 221 °C and with air injection fluxes ranging from 0.40 to 2.28 m3(ST)·m–2·h–1. Low temperature oxidation occurred in three successive periods: the induction period during which the oxygen depletion in the reactor exit stream remained small, the middle period characterized by peaks in oxygen depletion and carbon oxide concentrations, and the tailing period corresponding to very gradual decreases in oxygen depletion and carbon oxide concentrations. The extents of oxidation measured in our tests ranged from 29 to 37 moles O2/kg oil. Soil samples treated at temperatures between 167 and 176 °C met all the Tier 1 levels of the Canada Wide Standard for PHCs in coarse-grained surface soils, except those for soil contact and protection of ground water. Concentrations of individual polycyclic aromatic hydrocarbons (PAHs) in the soil samples treated at 167 and 176 °C complied with the Canadian Environmental Quality Guidelines for all soil types. Key words: low temperature oxidation, petroleum hydrocarbons, remediation, soil, motor oil.
Non-enzymatic degradation of chlorofluorocarbon 113 using cyanocobalamin under anaerobic conditions
Authors: Bagley David M , Sutherland Ian G , Sleep Brent E
Published: October 2004

Chlorofluorocarbon 113 (CFC113) was rapidly and completely degraded non-enzymatically in systems containing cyanocobalamin with titanium (III) citrate as the reductant. Hydrochlorofluorocarbon 123a (HCFC123a) accounted for up to 25% of the degraded CFC113. Chlorotrifluoroethene was also detected. Increasing concentrations of cyanocobalamin increased CFC113 removal rates asymptotically and also decreased the fraction of HCFC123a remaining. Key words: chlorofluorocarbon 113, cyanocobalamin, anaerobic degradation, non-enzymatic.
Décoloration des eaux usées de levurerie par adsorption sur charbon
Authors: Tahar Faouzi Ben , Cheikh Ridha Ben , Blais Jean François
Published: October 2004

The decolorization study of a yeast wastewater factory by adsorption on activated and raw charcoal showed that these adsorbents have great capacity to discolor and to adsorb the total organic matter (TOM), the chemical oxygen demand (COD), and the dissolved organic carbon (DOC). The solutions color characteristics have been followed by determining their dominant wavelengths issued from their correspondent trichromatic coefficients (X,Y,Z). The adsorbent size is an important parameter. The use of 30 g of charcoal sized 150250 µm, per liter of solution, leads to a total decolorization, and to a diminution of up to 50% of the treated solutions COD and DOC concentrations. To obtain the same efficiency, 130 g/L of 425- to 850-µm sized charcoal are needed. The study of the kinetics of the discoloration shows that the adsorbent instantly reaches a saturated state with a saturation rate almost equivalent to the rate of its diffusion in the liquid. It shows also that the maximum amounts of the adsorption of the COD and the DOC can be modelled by the Langmuir adsorption isotherm, and that they are respectively equal to 231 and 213 mg/g for the nonactivated charcoal (150250 µm), and 103 mg/g for the activated charcoal (425850 µm) regarding the COD, and that the Freundlich adsorption model fit well the COD and DOC adsorption for the nonactivated charcoal. Key words: decolorization, charcoal, adsorption, yeast, wastewater.
Friction and confinement effects on a shallow recirculating flow
Authors: Chu Vincent H , Liu Fang , Altai Wihel
Published: October 2004

Experiments were conducted to study confinement and friction effects on a shallow recirculating flow that was formed in a lateral expansion of an open-channel flow on a smooth bed. Dye was introduced to the flow as tracer. The instantaneous dye concentration in the flow was captured by video simultaneously across the width and along the length of the flume. The mean and the root-mean-square values of the dye-concentration fluctuations at selected cross sections along the flow are analyzed and compared with a previous series of data that were collected using a probe to measure the concentration one point at a time. The previous experiment was conducted in a small flume on a roughen bed. The new flume in the present experiment was 2.35 times wider. The large width of the new flume facilitates the study of the same friction effect on a smooth bed over a greater range of the confinement effect. In comparison with the previous experiments, the dye concentration in the present experiments is higher for the same range of bed-friction numbers. The difference in the results is tentatively attributed to the bed-generated turbulence. Key words: recirculating flow, shallow open-channel flow, quasi-two-dimensional turbulent flow, horizontal turbulence, bed-generated turbulence, friction effects, tracer concentration measurements, video imaging method.
Horizontal dispersion in the surface layer of a long narrow lake
Authors: Stevens C L , Lawrence Gregory A , Hamblin P F
Published: October 2004

Dye tracer experiments were conducted in the surface layer of Kootenay Lake, British Columbia. Estimates of the coefficient of horizontal diffusivity range from 0.01 to 13 m2 s–1. In some instances the diffusion rate increased more rapidly as a function of scale than expected based on empirical generalizations from the oceans and smaller lakes. The experiments illustrate the role of shear dispersion and internal waves. Key words: lake dispersion, stratification, dye tracing, turbulent diffusion, mixing, wind stress.
A dynamically coupled outfall plume-circulation model for effluent dispersion in Burrard Inlet, British Columbia
Authors: Li Sheng , Hodgins Donald O
Published: October 2004

A circulation-water quality model, coupled with an outfall plume model, has been developed, to predict three-dimensional circulation and effluent dispersion as functions of circulation forcing, ocean turbulent mixing, discharge rate and diffuser parameters. The coupled model was applied to the Lions Gate outfall discharging sewage into Burrard Inlet, British Columbia; in this case, the circulation was driven by the tides and density variations. The model results have good agreement with dye survey data and acoustic Doppler current profiler (ADCP) measurements from the inlet. Under typical oceanographic conditions for the area, the model predicts submerged plumes below 8 m depth at most times. Short-lived surfacing occurs for a few minutes at slack tide. The near-field trapping level and initial dilution are controlled by tidal flows through First Narrows and the effluent discharge rate. Key words: outfall, diffuser, numerical model, dispersion, circulation, dilution, plume, Burrard Inlet.
Dispersion of heavy particles in an isolated pancake-like vortex
Authors: Goater Aurelie , Lawrence Gregory A
Published: October 2004

The objective of this study is to characterize the dispersion of particles (mainly heavy particles) in a quasi two-dimensional axisymmetric pancake-like vortex. The velocity field for a pancake vortex is substituted into the Maxey-Riley equation, and the resulting equations are solved numerically. Particles that are denser than the surrounding fluid always move away from the vortex center. When the flow is initially seeded with a homogeneous distribution of particles of the same size and density, the particles accumulate in the outer region of the vortex. In addition, overtaking occurs if the Stokes number is large enough. The analysis of the concentration profiles in the horizontal plane of the vortex shows that accumulation of particles takes the form of a concentration wave that grows and travels away from the vortex center. A second peak of concentration appears when overtaking occurs. These concentration peaks dramatically increase the potential for collisions between particles and the potential for flocculation. Three-dimensional simulations show that this second peak only occurs when the vortex is sufficiently thick. Key words: particle dispersion, pancake vortex, Maxey-Riley equation, concentration profiles, flocculation.
Multiple pathways for cationic amino acid transport in rat thyroid epithelial cell line PC Cl3
Authors: Verri Tiziano , Dimitri Cinzia , Treglia Sonia , Storelli Fabio , De Micheli Stefania , Ulianich Luca , Vito Pasquale , Marsigliante Santo , Storelli Carlo , Di Jeso Bruno
Published: October 2004

Information regarding cationic amino acid transport systems in thyroid is limited to Northern blot detection of y+LAT1 mRNA in the mouse. This study investigated cationic amino acid transport in PC cell line clone 3 (PC Cl3 cells), a thyroid follicular cell line derived from a normal Fisher rat retaining many features of normal differentiated follicular thyroid cells. We provide evidence that in PC Cl3 cells plasmalemmal transport of cationic amino acids is Na+ independent and occurs, besides diffusion, with the contribution of high-affinity, carrier-mediated processes. Carrier-mediated transport is via y+, y+L, and b0,+ systems, as assessed by l-arginine uptake and kinetics, inhibition of l-arginine transport by N-ethylmaleimide and neutral amino acids, and l-cystine transport studies. y+L and y+ systems account for the highest transport rate (with y+L > y+) and b0,+ for a residual fraction of the transport. Uptake data correlate to expression of the genes encoding for CAT-1, CAT-2B, 4F2hc, y+LAT1, y+LAT2, rBAT, and b0,+AT, an expression profile that is also shown by the rat thyroid gland. In PC Cl3 cells cationic amino acid uptake is under TSH and/or cAMP control (with transport increasing with increasing TSH concentration), and upregulation of CAT-1, CAT-2B, 4F2hc/y+LAT1, and rBAT/b0,+AT occurs at the mRNA level under TSH stimulation. Our results provide the first description of an expression pattern of cationic amino acid transport systems in thyroid cells. Furthermore, we provide evidence that extracellular l-arginine is a crucial requirement for normal PC Cl3 cell growth and that long-term l-arginine deprivation negatively influences CAT-2B expression, as it correlates to reduction of CAT-2B mRNA levels.
Disruption of microtubular network attenuates histamine-induced dilation in rat mesenteric vessels
Authors: de Arêdes Brum Carla , Duarte Igor Dimitri Gama , Webb R. Clinton , Leite Romulo
Published: October 2004

Cytoplasmic microtubules are important in many cellular homeostatic processes in the cell. They regulate cell shape and movement as well as serving as a network by which vesicles and membrane-bound organelles can travel. Lately, there have been many studies demonstrating that microtubules are involved in regulation of intracellular signaling and, therefore, affect vascular reactivity. In this study, we tested the hypothesis that microtubule disruption attenuates agonist-induced endothelium-dependent vasodilation. Isolated mesenteric arterial bed from normotensive rats was preconstricted with phenylephrine, and dose-response curves for histamine, acetylcholine (ACh), sodium nitroprusside (SNP), and pinacidil were performed before and after incubation with nocodazole or colchicine. Treatment of the vascular beds with nocodazole or colchicine significantly attenuated histamine relaxation but did not change the ACh-, SNP-, or pinacidil-induced vasorelaxation. Nocodazole did not cause an additional attenuation of the histamine-mediated dilation in mesenteric vessels in the presence of Nω-nitro-l-arginine methyl ester, high extracellular K+, or K+ channel blockers. These data suggest that disruption of microtubules affects an essential endothelial component of histamine-mediated vasodilation in the mesenteric arterial bed. The mechanism(s) involved in this effect might be related to an impairment of endothelial NO synthesis, which might not be as important for the ACh as for the histamine vasodilator response in rat mesenteric vessels. These results demonstrate the importance of the microtubular system for endothelium-dependent NO-mediated smooth muscle relaxation.
Aging influences cellular and molecular responses of apoptosis to skeletal muscle unloading
Authors: Siu Parco M. , Pistilli Emidio E. , Butler David C. , Alway Stephen E.
Published: October 2004

The influence of aging on skeletal myocyte apoptosis is not well understood. In this study we examined apoptosis and apoptotic regulatory factor responses to muscle atrophy induced via limb unloading following loading-induced hypertrophy. Muscle hypertrophy was induced by attaching a weight to one wing of young and aged Japanese quails for 14 days. Removing the weight for 7 or 14 days after the initial 14 days of loading induced muscle atrophy. The contralateral wing served as the intra-animal control. A time-released bromodeoxyuridine (BrdU) pellet was implanted subcutaneously with wing weighting to identify activated satellite cells/muscle precursor cells throughout the experimental period. Bcl-2 mRNA and protein levels decreased after 7 days of unloading, but they were unchanged after 14 days of unloading in young muscles. Bcl-2 protein level but not mRNA level decreased after 7 days of unloading in muscles of aged birds. Seven days of unloading increased the mRNA level of Bax in muscles from both young and aged birds. Fourteen days of unloading increased mRNA and protein levels of Bcl-2, decreased protein levels of Bax, and decreased nuclear apoptosis-inducing factor (AIF) protein level in muscles of aged birds. BrdU-positive nuclei were found in all unloaded muscles from both age groups, but the number of BrdU-positive nuclei relative to the total nuclei decreased after 14 days of unloading compared with 7 days of unloading. The TdT-mediated dUTP nick end labeling (TUNEL) index was higher after 7 days of unloading in both young and aged muscles and after 14 days of unloading in aged muscles. Immunofluorescent staining revealed that almost all of the TUNEL-positive nuclei were also BrdU immunopositive, suggesting that activated satellite cell nuclei (both fused and nonfused) underwent nuclear apoptosis during unloading. There were significant correlations among levels of Bcl-2, Bax, and AIF and TUNEL index. Our data are consistent with the hypothesis that apoptosis regulates, at least in part, unloading-induced muscle atrophy and loss of activated satellite cell nuclei in previously loaded muscles. Moreover, these data suggest that aging influences the apoptotic responses to prolonged unloading following hypertrophy in skeletal myocytes.
Nitric oxide mediates increased P-glycoprotein activity in interferon-γ-stimulated human intestinal cells
Authors: Dixit Santosh G. , Zingarelli Basilia , Buckley Donna J. , Buckley Arthur R. , Pauletti Giovanni M.
Published: October 2004

Patients with refractory inflammatory bowel disease (IBD) exhibit increased expression of intestinal P-glycoprotein (P-gp) as well as elevated luminal IFN-γ and nitric oxide (NO) levels. Using the in vitro Caco-2 cell culture model, we investigated whether these pathological mediators associated with the etiology of IBD affect functional activity of intestinal efflux systems. IFN-γ reduced cellular uptake of cyclosporin A (CysA) but not methotrexate (MTX) in a time- and concentration-dependent manner. Simultaneously, P-gp expression increased by approximately twofold. Coincubation with the inducible NO synthase inhibitor l- N6-(1-iminoethyl)lysine (l-NIL) dramatically reduced production of intracellular NO in response to IFN-γ stimulus. The presence of l-NIL also abrogated the cytokine-mediated increase in P-gp expression and function suggesting that NO is required for IFN-γ-mediated activation of this efflux system. Exposure of Caco-2 cells to the chemical NO donor S-nitroso- N-acetylpenicillamine (SNAP) produced a concentration-dependent decrease in intracellular CysA accumulation that was paralleled by an increase in P-gp expression. Both IFN-γ and SNAP enhanced DNA binding of NF-κB, whereas inclusion of l-NIL dramatically decreased this cytokine-induced effect on NF-κB binding. These results suggest that NO mediates IFN-γ-induced increase in expression and function of intestinal P-gp in the human Caco-2 cell culture model by altering DNA binding of NF-κB, which may enhance transcription of the ABCB1 gene encoding for this efflux system.
Levosimendan improves LV systolic and diastolic performance at rest and during exercise after heart failure
Authors: Tachibana Hideo , Cheng Heng-Jie , Ukai Tomohiko , Igawa Akihiko , Zhang Zhu-Shan , Little William C. , Cheng Che-Ping
Published: October 2004

The new myofilament Ca2+ sensitizer levosimendan (LSM) is a positive inotropic and vasodilatory agent. Its beneficial effects have been demonstrated at rest in congestive heart failure (CHF). However, its effect during exercise (Ex) in CHF is unknown. We assessed the effects of LSM on left ventricular (LV) dynamics at rest and during Ex in eight conscious, instrumented dogs with pacing-induced CHF. After CHF, with dogs at rest, LSM decreased arterial elastance ( Ea) and increased LV contractile performance as assessed by the slope of LV pressure-volume (P-V) relation. LSM caused a >60% increase in the peak rate of mitral flow (dV/d tmax) due to decreases in minimal LV pressure and the time constant of LV relaxation (τ). LV arterial coupling, quantified as the ratio of end-systolic elastance ( Ees) to Ea, was increased from 0.47 to 0.85%. LV mechanical efficiency, determined as the ratio of stroke work to total P-V area, was improved from 0.54 ± 0.09 to 0.61 ± 0.07. These beneficial effects persisted during Ex after CHF. Compared with CHF Ex dogs, treatment with LSM prevented Ex-induced abnormal increases in mean left atrial pressure and end-diastolic pressure and decreased Ees/ Ea. With LSM treatment during CHF Ex, the early diastolic portion of the LV P-V loop was shifted downward with decreased minimal LV pressure and τ values and a further augmented dV/d tmax. Ees/ Ea improved, and mechanical efficiency further increased from 0.61 ± 0.07 to 0.67 ± 0.07, which was close to the value reached during normal Ex. After CHF, LSM produced arterial vasodilatation; improved LV relaxation and diastolic filling; increased contractility, LV arterial coupling, and mechanical efficiency; and normalized the response to Ex.
Forearm neurovascular responses during mental stress and vestibular activation
Authors: Carter Jason R. , Cooke William H. , Ray Chester A.
Published: October 2004

Autonomic responses may underlie associations among anxiety, vestibular dysfunction, and unexplained syncope. Mental stress (MS), an anxiety-inducing stimulus, causes forearm vasodilation, whereas the vestibulosympathetic reflex (VSR) causes forearm vasoconstriction. The purpose of this study was to examine the combined effects of mental and vestibular stimulation on neurovascular control in the forearm. Heart rate, arterial pressure (Finapres), and forearm blood flow (Doppler) were measured in 10 healthy volunteers in the prone position during 1) head-down rotation (HDR), 2) MS (mental arithmetic), and 3) HDR + MS. Forearm vascular resistance (FVR) increased during HDR (from 232 ± 40 to 319 ± 53 units) and decreased during MS (from 260 ± 57 to 154 ± 22 units). During HDR + MS, FVR did not change [change (Δ) = −31 ± 50 units] and was not significantly different from the algebraic sum of each trial performed alone (Δ = −20 ± 42 units). Arm muscle sympathetic nerve activity (MSNA; microneurography) was measured in seven additional subjects. MSNA increased during HDR (from 13 ± 2 to 17 ± 2 bursts/min) and HDR + MS (from 11 ± 2 to 16 ± 2 bursts/min). Increases in MSNA during HDR + MS (Δ = 5 ± 2 bursts/min) were not different from the algebraic sum of each trial performed alone (Δ = 6 ± 2 bursts/min). We conclude that an additive neurovascular interaction exists between MS and the VSR in the forearm. Activation of the VSR prevented forearm vasodilation during MS, suggesting that activation of the VSR may help protect against stress-induced syncope.