bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rapid and sensitive CE method with field‐enhanced sample injection and in‐capillary derivatization for selenomethionine metabolism catalyzed by flavin‐containing monooxygenases
Authors: Hai Xin , Nauwelaers Thomas , Busson Roger , Adams Erwin , Hoogmartens Jos , Van Schepdael Ann 
Published: September 2010

AbstractA rapid and sensitive electrophoretically mediated microanalysis method with field‐enhanced sample injection (FESI) for in‐capillary derivatization was developed to determine selenomethionine (SeMet) and selenomethionine selenoxide (SeOMet). Phthalic anhydride (PA) was selected as the derivatization reagent due to the fast reaction at room temperature and the stability of derivatives. The in‐capillary derivatization was accomplished by electrophoretically mixing PA and sample plugs. PA reagent was introduced hydrodynamically into the capillary, whereas the sample solution was injected electrokinetically, thus allowing a selective preconcentration of the analytes by FESI. For FESI, the optimum sample solvent was 2 mM borate solution. The borate buffer was suitable for both in‐capillary derivatization and separation of the derivatives. The combination of electrophoretically mediated microanalysis with FESI for in‐capillary derivatization was successfully achieved with about 800‐fold concentration sensitivity enhancement compared to direct CE‐UV detection in the same setup. The present method is miniaturized and fully automated, which ensures the on‐line derivatization, stacking, separation and detection in 10 min. Finally, the developed method was successfully applied to measure enzyme activities by analyzing the reaction mixtures of SeMet with human flavin‐containing monooxygenases (FMO). The results showed that both FMO1 and FMO3, but not FMO5 could catalyze the Se‐oxygenation of SeMet.
Comparative enantioseparations of pharmaceuticals in capillary electrochromatography on polysaccharide‐based chiral stationary phases containing selectors with or without chlorinated derivatives
Authors: Hendrickx Ans , Mangelings Debby , Chankvetadze Bezhan , Vander Heyden Yvan 
Published: September 2010

AbstractThe screening conditions of an existing chiral strategy in CEC were tested for their applicability on four chlorine‐containing polysaccharide‐based stationary phases. The selectors of these phases are cellulose tris(3‐chloro‐4‐methylphenylcarbamate), amylose tris(5‐chloro‐2‐methylphenylcarbamate), cellulose tris(4‐chloro‐3‐methylphenylcarbamate) and cellulose tris(3,5‐dichlorophenylcarbamate). The enantioselectivity of these phases was compared with those of the four phases without chlorine (Chiralpak® AD‐RH, Chiralcel® OD‐RH, Chiralpak® AS‐RH and Chiralcel® OJ‐RH) used in the earlier defined strategy. A test set of 48 structurally diverse drug compounds was analyzed using the screening conditions of the strategy. These results led to possibilities to upgrade the current screening strategy so that improved success rates are obtained. The chlorine‐containing chiral stationary phases demonstrated an added value to the screening process since they showed enantioresolution for compounds not resolved by the chiral stationary phases not containing chlorine in their structure.
A novel 18O inverse labeling‐based workflow for accurate bottom‐up mass spectrometry quantification of proteins separated by gel electrophoresis
Authors: Santos Hugo M. , Glez‐Peña Daniel , Reboiro‐Jato Miguel , Fdez‐Riverola Florentino , Diniz Mário S. , Lodeiro Carlos , Capelo‐Martínez José‐Luis 
Published: September 2010

AbstractIn the present work we report on a novel and fast protocol for accurate bottom‐up protein quantification that overcomes the drawbacks of in‐gel digestion and MALDI analysis, while maintaining their benefits. It relies on the following steps: (i) gel electrophoresis separation of proteins, (ii) fast in‐gel protein digestion with trypsin, (iii) 18O‐labeling through the decoupled method, (iv) quantification through selected peptides previously chosen using the 18O inverse labeling approach and that, finally, (v) it takes advantage of software specifically developed to select the peptides that will drive the quantification of the protein in an automated mode. We have accurately quantified the following six proteins: glycogen phosphorylase, BSA, ovalbumin, carbonic anhydrase, trypsin inhibitor, and α‐lactalbumin. As a case study we have quantified the protein vitellogenin in plasma of Cyprinus carpio exposed to high levels of estrogens. The proposed new protocol was validated against the traditional ELISA method; both were found to provide comparable results (non‐parametric Mann–Whitney U‐test).
Simultaneous sizing and electrophoretic mobility measurement of sub‐micron particles using Brownian motion
Authors: Palanisami Akilan , Miller John H. 
Published: September 2010

AbstractThe size and surface chemistry of micron scale particles are of fundamental importance in studies of biology and air particulate pollution. However, typical electrophoretic measurements of these and other sub‐micron scale particles (300 nm–1 μm) cannot resolve size information within heterogeneous mixtures unambiguously. Using optical microscopy, we monitor electrophoretic motion together with the Brownian velocity fluctuations – using the latter to measure size by either the Green–Kubo relation or by calibration from known size standards. Particle diameters are resolved to ±12% with 95% confidence. Strikingly, the size resolution improves as the particle size decreases due to the increased Brownian motion. The sizing ability of the Brownian assessed electrophoresis method described here complements the electrophoretic mobility resolution of the traditional CE.
Highly sensitive trivalent copper chelate‐H2O2 system for CE‐chemiluminescent detection of luminol‐type compounds
Authors: Fu Zhifeng , Li Zongyun , Xie Haoyue , Li Tao , Li Cuifang 
Published: September 2010

AbstractLuminol‐type compounds can be used as chemiluminescent (CL) derivatization reagents for amines, carboxylic acids and protein. Copper chelate diperiodatocuprate(III) (K5[Cu(HIO6)2], DPC) was synthesized by complexation of copper at trivalent oxidation state and periodate in a strong basic medium. It was found that DPC can greatly enhance the reaction between luminol‐type compounds and H2O2 to produce very strong CL emission. Based on this fact, a rapid CE method combined with high‐sensitive end‐column CL detection was established to simultaneously analyze luminol and N‐(4‐aminobutyl)‐N‐ethylisoluminol (ABEI) with wide concentration range of 3.0–300 nmol/L in 5 min. The RSDs of the signal intensity and the migration time were less than 3.9 and 7.0% for a standard sample containing 100 nmol/L luminol and ABEI (n=5), respectively. The investigation implies that DPC is a promising sensitizer for CE‐CL detection of a great variety of biomolecules and drugs in biological samples after derivatization using luminol derivatives.
Stressin' Sestrins take an aging fight
Authors: Budanov Andrei V. , Lee Jun Hee , Karin Michael 
Published: September 2010

AbstractSestrins (Sesns) are a family of highly conserved stress‐responsive proteins, transcriptionally regulated by p53 and forkhead transcription factor that exhibit oxidoreductase activity in vitro and can protect cells from oxidative stress. However, their major biochemical and physiological function does not appear to depend on their redox (reduction and oxidation) activity. Sesns promote activation of adenosine‐5′‐monophosphate (AMP)‐dependent protein kinase in both mammals and flies. Stress‐induced Sesn expression results in inhibition of the target of rapamycin complex 1 (TORC1) and the physiological and pathological implications of disrupting the Sesns‐TORC1 crosstalk are now being unravelled. Detailing their mechanism of action and exploring their roles in human physiology point to exciting new insights to topics as diverse as stress, cancer, metabolism and aging.
Channel and floodplain sediment dynamics in a reach of the tropical meandering Rio Beni (Bolivian Amazonia)
Authors: Gautier Emmanuèle , Brunstein Daniel , Vauchel Philippe , Jouanneau Jean‐Marie , Roulet Marc , Garcia Coral , Guyot Jean‐Loup , Castro Marcello 
Published: September 2010

AbstractThe study investigates interactions, water and sediment exchanges, between a rapidly migrating meander and its associated floodplain at fine temporal and spatial scales. The Beni River, an Amazonian free meandering river, makes the transition between Andean ranges and Amazonian lowlands. For the period 2002–2006, an assemblage of tools and methods (water and sediment discharges, topometric and bathymetric surveys, sedimentation rate estimations from unsupported 210Pb and sediment trapping system) was used to jointly analyse the influence on the sediment budget of external factors (mainly water and sediment discharge) and the inherent behaviour of the system. The main issue addressed is the investigation of the complex relationship between ‘morphological conditioning’ of fluvial landform and process. The first part of the study was undertaken with the aim of linking erosion–deposition in an active meander with water and sediment fluxes. The three inter‐annual evolutions are characterized by very unequal sediment budgets; the first two intervals underwent predominant erosion, and the latter slight accumulation. Digital elevation models, evaluated for the active meander, demonstrate that sedimentation on the point bar depends more on external factors than erosion of the concave bank, which fluctuates slightly. The second part of the study, focusing on water and sediment exchanges between active bend and floodplain, examines the respective parts played by overbank flow and by an abandoned channel on the diffusion and sequestration of sediment. The association of short‐ and long‐term estimation of sedimentation rates suggests that floodplain construction is associated with two different processes and rhythms of sediment transportation. Finally, a sediment budget is proposed for the Beni River in the upper part of the Amazonian lowlands. Copyright © 2010 John Wiley & Sons, Ltd.
Formative conditions and sedimentary structures of sandy 3D antidunes: an application of the gravel step‐pool model to fine‐grained sand in an experimental flume
Authors: Yokokawa Miwa , Hasegawa Kazuyoshi , Kanbayashi Satoru , Endo Noritaka 
Published: September 2010

AbstractAntidunes and their sedimentary structures can be useful in reconstructing paleo‐hydraulic conditions, especially for large discharge events. However, three‐dimensional (3D) antidunes in sand‐sized sediments have not yet been studied extensively, as compared to either two‐dimensional (2D) antidunes or antidunes in gravel‐sized sediments. In this study, we estimated formative conditions of gravel step‐pool morphologies and applied them to the formation of 3D antidunes over a sand bed. Formative conditions are expressed in terms of a relationship between the water discharge per unit width and the bed slope. Flume experiments demonstrated that 3D mound‐like antidune configurations and their associated internal sedimentary structures could be preserved. Internal sedimentary structures were characterized by shallow lens‐like structures whose bases were erosional. Although gently‐dipping concave‐upward lamination was dominant, convex‐upward lamination was occasionally observed. The dimensions of lenticular lamina‐sets can be used to estimate antidune geometry. Thus if 3D antidunes can be interpreted in the stratigraphic record, it is possible to estimate the paleo‐hydraulic parameters such as water discharge and bed slope more precisely than previously. Copyright © 2010 John Wiley & Sons, Ltd.
The nature and transport of the fine‐grained component of Swift Creek Landslide, Northwest Washington
Authors: Bayer Tovah M. , Linneman Scott 
Published: September 2010

AbstractExtreme sedimentation in Swift Creek, located in the Cascades foothills in NW Washington (48°55′N, 122°16′W), results from erosion of the oversteepened, unvegetated toe of a large (55 hectares) active landslide. Deposition of landslide‐derived sediment has necessitated costly mitigation projects in the channel including annual dredging and temporary sediment traps in an attempt to reduce the risk of flooding and damage to man‐made structures downstream. This study attempts to understand the process of sediment production along with the corresponding erosion rates of the sediment source to help with the development of mitigation plans and construction of optimal sediment reservoirs.The bedload and suspended sediment in the creek are a direct result of the weathering process of the serpentinitic bedrock underlying the landslide. The serpentinite does not weather to smectite clay, as previously thought. Instead, it weathers to asbestiform chrysotile with minor amounts of chlorite, illite and hydrotalcite, all of which occur in clay seeps on the unvegetated surface of the landslide. The chrysotile fibers average 2 µm in length and make up at least 50%, by volume, of the suspended load transported in Swift Creek. This study does not address the environmental or health implications of the asbestiform chrysotile transport or deposition.During the sampled time between February 2005 and February 2006, 127 discrete suspended sediment samples were collected and discharge was measured 66 times. The suspended sediment concentrations ranged from 0·02 g L−1 to 41·6 g L−1 and the discharge ranged from 0·0 m3 s−1 to 0·5 m3 s−1. A nonlinear functional model estimated the total suspended sediment flux from detailed precipitation records and discrete suspended sediment concentration and discharge measurements to be 910 t km−2 yr−1. When the suspended sediment flux is coupled with estimates of downstream deposition of coarse sediment, the estimated erosion rate for the entire Swift Creek landslide is 158 mm yr−1. The majority of the material entering Swift Creek is presumed to originate on the unvegetated toe of the landslide, for which the erosion rate is thus approximately 1 m yr−1. Copyright © 2010 John Wiley & Sons, Ltd.
Nonlinearity and unsteadiness in river meandering: a review of progress in theory and modelling
Authors: Pittaluga Michele Bolla , Seminara Giovanni 
Published: September 2010

AbstractRiver meandering has been extensively investigated. Two fundamental features to be explored in order to make further progress are nonlinearity and unsteadiness. Linear steady models have played an important role in the development of the subject but suffer from a number of limits. Moreover, rivers are not steady systems; rather their states respond to hydrologic forcing subject to seasonal oscillations, punctuated by the occurrence of flood events. We first derive a classification of river bends based on a systematic assessment of the various physical mechanisms affecting their morphodynamic equilibrium and their evolution in response to variations of hydrodynamic forcing. Using the database by Lagasse et al. (2004) we also show that natural meanders are typically mildly curved and long, i.e. such that both the centrifugal and the topographic secondary flows are weak, but they are almost invariably nonlinear. We then review some recent developments which allow us to treat analytically the flow and bed topography of mildly curved and long nonlinear bends subject to steady forcing, taking advantage of the fact that flow and bed topography in mildly curved long bends are slowly varying. Results show that nonlinearity has a number of consequences: most notably damping of the morphodynamic response and upstream shifting of the location of the nonlinear peak of the flow speed. Next we extend the latter model to the case of unsteady forcing. Results are found to depend crucially on the ratio between the flood duration and a morphodynamic timescale. It turns out that, in a channel subject to a repeated sequence of floods, the system reaches a dynamic equilibrium. We conclude the paper discussing how the present assessment relates to the debate on meander modelling of the late 1980s and suggesting what we see as promising lines of future developments.
Novelty preference in patients with developmental amnesia
Authors: Munoz M. , Chadwick M. , Perez‐Hernandez E. , Vargha‐Khadem F. , Mishkin M. 
Published: September 2010

AbstractTo re‐examine whether or not selective hippocampal damage reduces novelty preference in visual paired comparison (VPC), we presented two different versions of the task to a group of patients with developmental amnesia (DA), each of whom sustained this form of pathology early in life. Compared with normal control participants, the DA group showed a delay‐dependent reduction in novelty preference on one version of the task and an overall reduction on both versions combined. Because VPC is widely considered to be a measure of incidental recognition, the results appear to support the view that the hippocampus contributes to recognition memory. A difficulty for this conclusion, however, is that according to one current view the hippocampal contribution to recognition is limited to task conditions that encourage recollection of an item in some associated context, and according to another current view, to recognition of an item with the high confidence judgment that reflects a strong memory. By contrast, VPC, throughout which the participant remains entirely uninstructed other than to view the stimuli, would seem to lack such task conditions and so would likely lead to recognition based on familiarity rather than recollection or, alternatively, weak memories rather than strong. However, before concluding that the VPC impairment therefore contradicts both current views regarding the role of the hippocampus in recognition memory, two possibilities that would resolve this issue need to be investigated. One is that some variable in VPC, such as the extended period of stimulus encoding during familiarization, overrides its incidental nature, and, because this condition promotes either recollection‐ or strength‐based recognition, renders the task hippocampal‐dependent. The other possibility is that VPC, rather than providing a measure of incidental recognition, actually assesses an implicit, information‐gathering process modulated by habituation, for which the hippocampus is also partly responsible, independent of its role in recognition. © 2010 Wiley Periodicals, Inc.
Bridging divergent neural models of recognition memory: Introduction to the special issue and commentary on key issues
Authors: Voss Joel L. , Paller Ken A. 
Published: September 2010

AbstractThis special issue reviews progress that has been made in recent years in understanding neural processing relevant for recognition memory. Here we describe how the nine reviews that comprise this issue weigh in on some of the most pressing and hotly debated issues in the study of recognition memory, including: (1) the number of processes that support recognition, (2) the nature of these processes, and (3) how these processes map onto neural processing events and brain structures. We then discuss the challenges inherent in attempting to incorporate the fundamentally different types of information that result from various cognitive neuroscience methods (e.g., electrophysiological recordings of neurons, lesion‐deficit studies, analyses of brain potentials and activations, modeling of behavioral responses, and phenomenological reports), and make suggestions for how to better integrate these disparate data types when making inferences about recognition memory. As the articles in this special issue make clear, great strides have been made in understanding how organisms are able to appreciate repetition. And yet, several controversies in this area have still not been resolved, but these articles clarify the core disagreements as well as the tests that must be conducted to seek resolution. This special issue as a whole should thus facilitate advancements in the future study of the neural mechanisms of recognition. © 2010 Wiley‐Liss, Inc.
Effects of adult‐generated granule cells on coordinated network activity in the dentate gyrus
Authors: Lacefield Clay O. , Itskov Vladimir , Reardon Thomas , Hen René , Gordon Joshua A. 
Published: September 2010

AbstractThroughout the adult life of most mammals, new neurons are continuously generated in the dentate gyrus of the hippocampal formation. Recent work has documented specific cognitive deficits after elimination of adult hippocampal neurogenesis in rodents, suggesting that these neurons may contribute to information processing in hippocampal circuits. Young adult‐born neurons exhibit enhanced excitability and have altered capacity for synaptic plasticity in hippocampal slice preparations in vitro. Still, little is known about the effect of adult‐born granule cells on hippocampal activity in vivo. To assess the impact of these new neurons on neural circuits in the dentate, we recorded perforant‐path evoked responses and spontaneous network activity from the dentate gyrus of urethane‐anesthetized mice whose hippocampus had been focally X‐irradiated to eliminate the population of young adult‐born granule cells. After X‐irradiation, perforant‐path responses were reduced in magnitude. In contrast, there was a marked increase in the amplitude of spontaneous γ‐frequency bursts in the dentate gyrus and hilus, as well as increased synchronization of dentate neuron firing to these bursts. A similar increase in gamma burst amplitude was also found in animals in which adult neurogenesis was eliminated using the GFAP:TK pharmacogenetic ablation technique. These data suggest that young neurons may inhibit or destabilize recurrent network activity in the dentate and hilus. This unexpected result yields a new perspective on how a modest number of young adult‐generated granule cells may modulate activity in the larger population of mature granule cells, rather than acting solely as independent encoding units. © 2010 Wiley Periodicals, Inc., Inc.
Hippocampal volumetrics in treatment‐resistant depression and schizophrenia: The devil's in De‐Tail
Authors: Maller Jerome J. , Daskalakis Zafiris J. , Thomson Richard H.S. , Daigle Melissa , Barr Mera S. , Fitzgerald Paul B. 
Published: September 2010

AbstractStudies of patients with major depressive disorder (MDD) and schizophrenia (SCH) have revealed reduced hippocampal volumes, but findings have been inconsistent due to sample and measurement differences. The current study sought to measure this structure in a large sample of MDD, SCH, and healthy subjects, using a strict measurement protocol, to elucidate morphological‐specific volumetric differences. Patients with treatment‐resistant MDD (N = 182) and treatment‐resistant SCH with auditory‐verbal hallucinations (N = 52), and healthy controls (N = 76) underwent psychiatric assessments and brain MRI. The findings indicate that (1) MDD and SCH patients have reduced total hippocampal volume which was marked in the tails (more so in patients with MDD), (2) region of interest estimation protocols and sample characteristics may help explain volumetric differences between previous SCH studies. © 2010 Wiley Periodicals, Inc., Inc.