bluuebunny/crossref_metadata_2025_split huggingface dataset:
Common deactivation patterns during working memory and visual attention tasks: An intra‐subject fMRI study at 4 Tesla
Authors: Tomasi Dardo , Ernst Thomas , Caparelli Elisabeth C. , Chang Linda 
Published: January 2006

AbstractThis parametric functional magnetic resonance imaging (fMRI) study investigates the balance of negative and positive fMRI signals in the brain. A set of visual attention (VA) and working memory (WM) tasks with graded levels of difficulty was used to deactivate separate but overlapping networks that include the frontal, temporal, occipital, and limbic lobes; regions commonly associated with auditory and emotional processing. Brain activation (% signal change and volume) was larger for VA tasks than for WM tasks, but deactivation was larger for WM tasks. Load‐related increases of blood oxygenation level‐dependent (BOLD) responses for different levels of task difficulty cross‐correlated strongly in the deactivated network during VA but less so during WM. The variability of the deactivated network across different cognitive tasks supports the hypothesis that global cerebral blood flow vary across different tasks, but not between different levels of task difficulty of the same task. The task‐dependent balance of activation and deactivation might allow maximization of resources for the activated network. Hum Brain Mapp, 2005. © 2006 Wiley‐Liss, Inc.
Extraction equilibria and separation of phenylalanine and aspartic acid from water with di(2‐ethylhexyl)phosphoric acid
Authors: Lin Su‐Hsia , Chen Chia‐Nan , Juang Ruey‐Shin 
Published: January 2006

AbstractThe distribution equilibria of single and binary L‐phenylalanine and L‐aspartic acid between water and a kerosene solution of di(2‐ethylhexyl)phosphoric acid (D2EHPA) were studied. It was shown that the distribution ratios of phenylalanine generally increased with increasing aqueous pH (2–5) in the D2EHPA concentration range 0.1–0.5 mol dm−3, but those of aspartic acid decreased with increasing solution pH. Different reaction stoichiometries were proposed for the extraction of phenylalanine and aspartic acid under the conditions studied. The extraction equilibrium constants were obtained. Competitive extraction in binary systems was more apparent in the pH range where the cationic form of amino acids was not predominant. The present results indicated that selective separation of phenylalanine to aspartic acid was possible with this cationic extractant when they were extracted at higher pH and stripped using higher acidity of HCl solution. Copyright © 2006 Society of Chemical Industry
Synthesis of a mesoporous material from two natural sources
Authors: Sanhueza Vilma , López‐Escobar Leopoldo , Kelm Ursula , Cid Ruby 
Published: January 2006

AbstractMesoporous materials were obtained from two natural silica sources, diatomite and pumicite, under hydrothermal conditions, autogenic pressure and in presence of the surfactant cetyltrimethylammonium bromide (CTAB) as the template. Using diatomite, a temperature of 383 K and the following molar ratios in the initial reaction gel: SiO2/Al2O3 = 8.86; CTAB/SiO2 = 0.1; Na2O/SiO2 = 0.10–0.25 and H2O/Na2O = 250–300, the mesoporous material MCM‐41 was obtained in a reaction time of 48 h. When pumicite was used, a mesoporous material was obtained in a reaction time of 96 h, a reaction temperature of 423 K and an initial reaction gel with the following molar ratios: SiO2/Al2O3 = 8.86; CTAB/SiO2 = 0.1; Na2O/SiO2 = 0.25 and H2O/Na2O = 330. Copyright © 2006 Society of Chemical Industry
Transient versus prolonged hyperlocomotion following lateral fluid percussion injury in mongolian gerbils
Authors: Li Shihong , Kuroiwa Toshihiko , Katsumata Noriko , Ishibashi Satoru , Sun Li Yuan , Endo Shu , Ohno Kikuo 
Published: January 2006

AbstractPosttraumatic hyperactivity is a neurobehavioral symptom commonly seen in patients after traumatic brain injury (TBI). No useful animal model has yet been established for evaluation of this important symptom. We induced either mild (MILD, 0.7–0.9 atm) or moderate (MOD, 1.3–1.6 atm) lateral fluid percussion injury (LFPI) in Mongolian gerbils. Open‐field and T‐maze tests were used during a 7‐day period after the trauma. All animals were perfusion fixed for histopathological examinations. Transient locomotor hyperactivity was found with a peak at 6 hr after injury in the MILD animals, whereas MOD animals showed prolonged and severe hyperlocomotion throughout the 7‐day posttrauma period (P < 0.0001). Interestingly, the temporal profile of the posttraumatic hyperactivity was similar to that of the working memory deficit in both injury groups. Histological examination revealed significant neural tissue damages, including cortical necrosis, white matter rarefaction, and neuronal loss in the hippocampus in the ipsilateral hemisphere of the MOD animals, vs. only negligible changes in the MILD animals. Correlation analysis revealed that the volume of white matter lesions was significantly correlated with both posttraumatic hyperactivity (r = 0.591, P < 0.01) and working memory deficit (r = −0.859, P < 0.0001). Taken together, our findings confirm the successful reproduction of posttraumatic hyperactivity following experimental TBI. The posttraumatic hyperlocomotion probably shared pathomechanisms common to those of cognitive dysfunction caused by LFPI, supporting the speculation from previous studies that some neurobehavioral abnormities intimately correlate with TBI‐induced cognitive dysfunction. Histopathologically, significant involvement of white matter damage in the posttraumatic functional deficits was indicated. © 2006 Wiley‐Liss, Inc.
Mitochondrial involvement in nitric oxide‐induced cellular death in cortical neurons in culture
Authors: Figueroa S. , Oset‐Gasque M.J. , Arce C. , Martinez‐Honduvilla C.J. , González M.P. 
Published: January 2006

AbstractNitric oxide (NO) is an unstable molecule with physiological and pathological properties. In brain, NO acts as a modulator of neurotransmission as well as a protector against neuronal death from several death stimuli. However, beside this protector effect, high NO concentrations produce neuronal death by a mechanism in which the caspase pathway is implicated. In this work, we demonstrate that in cortical neurons the NO toxicity is mediated by mitochondrial dysfunction. SNAP, an NO donor, induces apoptosis in these cells because it 1) increases the p53 and 2) induces cytochrome c release and activation of caspase‐9 and caspase‐3. SNAP also induces necrosis, through 1) breakdown of the mitochondrial membrane potential, 2) ATP decrease, 3) ROS formation, and 4) LDH and ATP release, indicative of oxidative stress and death by necrosis. To sum up, in cortical neurons, high NO concentrations produced cellular death by both an apoptotic and a necrotic mechanism in which the mitochondria are implicated. © 2006 Wiley‐Liss, Inc.
Brain dysmyelination and recovery assessment by noninvasive in vivo diffusion tensor magnetic resonance imaging
Authors: Harsan Laura A. , Poulet Patrick , Guignard Blandine , Steibel Jérôme , Parizel Nathalie , Loureiro de Sousa Paulo , Boehm Nelly , Grucker Daniel , Ghandour M. Said 
Published: January 2006

AbstractDiffusion tensor magnetic resonance imaging (DT‐MRI) was applied for in vivo quantification of myelin loss and regeneration. A transgenic mouse line (Oligo‐TTK) expressing a truncated form of the herpes simplex virus 1 thymidine kinase gene (hsv1‐tk) in oligodendrocytes was studied along with two induced phenotypes of myelin pathology. Myelin loss and axonal abnormalities differentially affect values of DT‐MRI parameters in the brain of transgenic mice. Changes in the anisotropy of the white matter were assessed by calculating and mapping the radial (D⊥) and axial (D∥) water diffusion to axonal tracts and fractional anisotropy (FA). A significant increase in D⊥ attributed to the lack of myelin was observed in all selected brain white matter tracts in dysmyelinated mice. Lower D∥ values were consistent with the histological observation of axonal modifications, including reduced axonal caliber and overexpression of neurofilaments and III β‐tubulin. We show clearly that myelination and axonal changes play a role in the degree of diffusion anisotropy, because FA was significantly decreased in dysmyelinated brain. Importantly, myelin reparation during brain postnatal development induced a decrease in the magnitude of D⊥ and an increase in FA compared with the same brain before recovery. The progressive increase in D∥ values was attributed to the gain in normal axonal morphology. This regeneration was confirmed by the detection of enlarged oligodendrocyte population, newly formed myelin sheaths around additional axons, and a gradual increase in axonal caliber. © 2006 Wiley‐Liss, Inc.
Ethanol promotes neuronal apoptosis by inhibiting phosphatidylserine accumulation
Authors: Akbar Mohammed , Baick Joseph , Calderon Frances , Wen Zhiming , Kim Hee‐Yong 
Published: January 2006

AbstractPrenatal and postnatal ethanol exposure induces abnormal cell death in the nervous system. We have previously reported that docosahexaenoic acid (DHA; 22:6n‐3) prevents neuronal apoptosis through promoting phosphatidylserine (PS) accumulation. Previously, we have shown in C6 glioma cells that ethanol inhibits the accumulation of PS caused by DHA supplementation. In this report, we demonstrate that in vitro or in vivo exposure to ethanol inhibits DHA‐dependent PS accumulation and neuronal survival. We found that Neuro 2A cells exposed to ethanol accumulated considerably less PS in response to the DHA enrichment and were less effective at phosphorylating Akt and suppressing caspase‐3 activity under serum‐starved or staurosporine‐treated conditions. The in vivo paradigm correlated well with the in vitro findings. We found that the total PS and DHA contents in the fetal hippocampus were slightly but significantly lowered by the prenatal ethanol exposure. Fetal hippocampal cultures obtained at embryonic day 18 from ethanol‐treated pregnant rats contained significantly higher apoptotic cells after 7 days in vitro under basal conditions and exhibited particular susceptibility to cell death induced by trophic factor removal in comparison with the pair‐fed control group. The reduction of PS and the resulting neuronal cell death inappropriately enhanced during development may contribute to the defects in brain function often observed in fetal alcohol syndrome. Published 2006 Wiley‐Liss, Inc.
Modulation of ERK and JNK activity by transient forebrain ischemia in rats
Authors: Shackelford Deborah A. , Yeh Richard Y. 
Published: January 2006

AbstractThe mitogen‐activated protein (MAP) kinase families of ERK and JNK participate in numerous intracellular signaling pathways and are abundantly expressed in the CNS. Activation of ERK and JNK during reperfusion of ischemic tissue is implicated in promoting cell death, insofar as inhibition of either pathway reduces neuronal cell death. However, ERK or JNK activation provides protection in other neuronal injury models. In this study, we monitored the concurrent modulation of ERK and JNK activity in the hippocampus, neocortex, and striatum during ischemia and immediately upon reperfusion in a rat model of transient global ischemia. All three regions incur a similar reduction in blood flow during occlusion but show different extents and temporal patterns of injury following reperfusion. ERK and JNK were active in the normal rat forebrain, and phosphorylation was reduced by ischemia. Upon reperfusion, ERK was rapidly activated in the hippocampus, neocortex, and striatum, whereas JNK phosphorylation increased in the hippocampus and striatum but not in the neocortex. The response of JNK vs. ERK more closely reflects the susceptibility of these regions. JNK1 was the predominant phosphorylated isoform. A minor pool of phosphorylated JNK3 increased above the control level after reperfusion in hippocampal but not in neocortical particulate fractions. In addition, a novel 32–35‐kDa c‐Jun kinase activity was detected in the hippocampus, neocortex, and striatum. The results show that ERK and JNK activities are rapidly, but not identically, modulated by ischemia and reperfusion and indicate that the MAP kinase pathways contribute to regulating the response to acute CNS injury. © 2006 Wiley‐Liss, Inc.
Phytoestrogen content of alfalfa cultivars grown in eastern Canada
Authors: Seguin Philippe , Zheng Wenju 
Published: January 2006

AbstractAlfalfa (Medicago sativa L.) contains several phytoestrogens that may have health‐promoting effects in humans. In this study, the concentrations of three phytoestrogens (apigenin, coumestrol, and luteolin) of ten field‐grown alfalfa cultivars were determined in the seeding and post‐seeding year at two sites in Sainte‐Anne‐de‐Bellevue, QC, Canada. Herbage and phytoestrogen yield per hectare were concurrently determined. Differences between cultivars were only observed for apigenin concentration and yield and coumestrol yield. There was a 37% variation between cultivars in apigenin concentration. Site‐by‐harvest interactions and harvest main effects were observed for the concentration and yield of all three phytoestrogens. There was a 2‐ and 2.5‐fold variation in coumestrol and luteolin concentrations, respectively, between harvests of both sites. Coumestrol concentration was lower in harvests of the seeding than of the post‐seeding year. Luteolin concentration fluctuated during the five harvests at one site, but was greater in the seeding than in the post‐seeding year at the other site. There was a 5.4‐fold variation in apigenin concentration between harvests of both sites, concentrations being lower in the seeding (avg. 173 µg g−1 DM) than in the post‐seeding year. Results suggest that choice of cultivars have limited impact on alfalfa phytoestrogen concentration, which, however, greatly differ between harvests and sites. Copyright © 2006 Society of Chemical Industry
Effect of semolina and absorption level on extrusion of spaghetti containing non‐traditional ingredients
Authors: Yalla Saujanya R , Manthey Frank A 
Published: January 2006

AbstractSpecific mechanical energy (SME), mechanical energy, extrusion rate and temperature of extruded spaghetti were monitored to determine the effects of semolina, hydration level and non‐traditional ingredients on pasta extrusion using a semi‐commercial pasta press with a fixed screw speed of 25 rpm. SME transferred to the dough during extrusion and the temperature of extruded spaghetti were greater with strong than with weak gluten semolina and at low than at high absorption levels. When compared with semolina hydrated to 300 g kg−1 absorption, SME transferred to the dough was 13 kJ kg−1 lower for semolina mixed with buckwheat (Fagopyrum esculentum Moench.) bran flour, 47 kJ kg−1 lower for semolina mixed with flaxseed (Linum usitativissimum L.) flour and 7 kJ kg−1 lower for semolina mixed with wheat (Triticum turgidum var. durum L.) bran. Weak gluten semolina, high absorption levels and non‐traditional ingredients reduced the mechanical energy required for extrusion more than they reduced extrusion rate. The target temperature for extruded spaghetti was 45 °C. The temperature of extruded spaghetti containing flaxseed flour was below 45 °C whereas the temperature of spaghetti containing wheat bran was above 45 °C, regardless of semolina type or absorption level. Copyright © 2006 Society of Chemical Industry
Solvent effect on the alkaline hydrolysis of 2‐thiophenyl‐ 3,5‐dinitropyridine
Authors: Fathalla Magda F. 
Published: January 2006

AbstractThe kinetics of the alkaline hydrolysis of 2‐thiophenyl‐3,5‐dinitropyridine were studied spectrophotometrically in different aquo‐organic solvents such as methanol, ethanol, n‐propyl alcohol, iso‐propyl alcohol, t‐butyl alcohol, acetonitrile, dimethyl sulfoxide, dioxane, and acetone at 30°C with various solvent compositions up to 80% (v/v) of organic components. An increase in the organic solvent percentage (v/v) has different effects on the reaction rate constants presumably due to hydrogen bond donor HBD and acceptor HBA of the medium and other solvatochromic parameters. Linear and nonlinear plots of log k against the reciprocal of the dielectric constant of the solvent were obtained. The effects are too complex to be analyzed in terms of a single parameter, but an approach using the Kamlet–Taft solvatochromic parameters is applied successfully to six mixed aquo‐organic solvent systems. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 159–165, 2006
Studies on the kinetics of imidazolium fluorochromate oxidation of some meta‐ and para‐substituted anilines in nonaqueous media
Authors: Bhuvaneshwari D. S. , Elango K. P. 
Published: January 2006

AbstractThe imidazolium fluorochromate (IFC) oxidation of meta‐ and para‐substituted anilines, in seven organic solvents, in the presence of p‐toluenesulfonic acid (TsOH) is first order in IFC and TsOH and is zero order with respect to substrate. The IFC oxidation of 15 meta‐ and para‐substituted anilines at 299–322 K complies with the isokinetic relationship but not to any of the linear free energy relationships; the isokinetic temperature lies within the experimental range. The specific rate of oxidizing species‐anilines reaction (k2) correlates with substituent constants affording negative reaction constants. The rate data failed to correlate with macroscopic solvent parameters such as εr and ENT. A correlation of rate data with Kamlet–Taft solvatochromic parameters (α, β, π*) suggests that the specific solute–solvent interactions play a major role in governing the reactivity, and the observed solvent effects have been explained on the basis of solute–solvent complexation. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 166–175, 2006
Ru(VI)‐catalyzed oxidation of alcohols by hexacyano‐ferrate(III): Computational analysis of mixed kinetic order
Authors: Mucientes A. E. , Herrero H. , Sanchez O. 
Published: January 2006

AbstractThe title reaction shows a mixed kinetic order with respect to hexacyanoferrate(III). The reaction tends to be single zero order at high [Fe(CN)] and single first order at low [Fe(CN)]. For this reason, the decay of the absorbance of hexacyanoferrate(III) at 420 nm changes from linear to exponential as the reaction proceeds. This change of order has also been observed in the initial moments of the reaction. The dependence of the reaction rate on [Fe(CN)] has been obtained, by computational methods, at t = 0 and at any subsequent time during the course of the reaction. The coincidence of both equations would indicate that none of the substances produced in the reaction acts as an activator or inhibitor. The mixed order is due to the comparable rates of complex decomposition and catalyst regeneration steps. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 153–158, 2006
Opposing action of curcumin and green tea polyphenol in human keratinocytes
Authors: Eckert Richard L. , Crish James F. , Efimova Tatiana , Balasubramanian Sivaprakasam 
Published: January 2006

AbstractPersistent environmental insult can convert a normal cell into a cancer cell. However, various natural chemopreventive agents called antioxidants can retard this progression. We have recently explored the effects of several chemopreventive agents, including green tea polyphenol and curcumin, on normal human keratinocyte function. Our findings suggest that a bioactive polyphenol from green tea, (–)‐epigallocatechin‐3‐gallate (EGCG), acts to increase involucrin gene expression, suggesting that EGCG treatment enhances normal human keratinocyte differentiation. Mechanistic studies indicate that EGCG alters mitogen‐activated protein kinase cascade function to activate involucrin gene transcription via a Ras, MEKK1, MEK3, ERK1/2–p38δ cascade that targets AP1 and CAATT enhancer binding protein transcription factors. These findings suggest that EGCG may inhibit disease progression by promoting keratinocyte differentiation. Parallel studies indicate that not all antioxidants produce a similar response. Curcumin, an antioxidant derived from the turmeric, antagonizes the EGCG‐dependent response by interfering in this signaling pathway. These studies suggest that different antioxidant may produce antagonistic effects in tissues.
Proton‐observed carbon‐edited NMR spectroscopy in strongly coupled second‐order spin systems
Authors: Henry Pierre‐Gilles , Marjanska Malgorzata , Walls Jamie D. , Valette Julien , Gruetter Rolf , Uǧurbil Kâmil 
Published: January 2006

AbstractProton‐observed carbon‐edited (POCE) NMR spectroscopy is commonly used to measure 13C labeling with higher sensitivity compared to direct 13C NMR spectroscopy, at the expense of spectral resolution. For weakly coupled first‐order spin systems, the multiplet signal at a specific proton chemical shift in POCE spectra directly reflects 13C enrichment of the carbon attached to this proton. The present study demonstrates that this is not necessarily the case for strongly coupled second‐order spin systems. In such cases NMR signals can be detected in the POCE spectra even at chemical shifts corresponding to protons bound to 12C. This effect is demonstrated theoretically with density matrix calculations and simulations, and experimentally with measured POCE spectra of [3‐13C]glutamate. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Fat attenuation using a dual steady‐state balanced‐SSFP sequence with periodically variable flip angles
Authors: Absil J. , Denolin V. , Metens T. 
Published: January 2006

AbstractA refocused‐SSFP sequence based on balanced‐FFE (TrueFisp, Fiesta) that attenuates fat signal is presented. The sequence uses periodically variable flip angles and produces a dual steady state of the signal, which is obtained after a dual transient phase if an appropriate preparation is used. The off‐resonance profile of the steady‐state signal exhibits large stopbands that can be employed for fat suppression. Numerical simulations were performed to investigate the signal behavior and the off‐resonance properties of the sequence. Experimental results obtained with a Philips Gyroscan Intera 1.5T MR scanner demonstrated fat attenuation in phantoms and abdominal images in volunteers. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
The updated BSR guidelines for anti‐TNF in adults with RA: What has changed and why?
Authors: Deighton Chris 
Published: January 2006

AbstractIn 2001 the British Society for Rheumatology (BSR) published guidelines for prescribing TNF‐αblockers in adults with rheumatoid arthritis (RA). In an unusual move, the National Institute of Clinical Excellence (NICE) accepted the BSR guidelines and published them unchanged and included them in their own Technology Appraisal (National Institute of Clinical Excellence, 2002). The field of anti‐TNF in RA is rapidly changing, and the BSR Standards, Guidelines and Audit Working Group decided in 2004 to update the guidelines. These were published in February 2005 (Ledingham and Deighton, 2005). This article summarizes the key changes, and attempts to justify them, using further data that has emerged since the updated guidelines were produced, and audit data from the Derby Rheumatology department. Copyright © 2005 John Wiley & Sons, Ltd.