bluuebunny/crossref_metadata_2025_split huggingface dataset:
17β‐estradiol protects against hypoxic/ischemic white matter damage in the neonatal rat brain
Authors: Gerstner Bettina , Lee Joan , DeSilva Tara M. , Jensen Frances E. , Volpe Joseph J. , Rosenberg Paul A. 
Published: February 2009

AbstractDeveloping oligodendrocytes (pre‐OLs) are highly vulnerable to hypoxic‐ischemic injury and associated excitotoxicity and oxidative stress. 17β‐Estradiol plays an important role in the development and function of the CNS and is neuroprotective. The sudden drop in circulating estrogen after birth may enhance the susceptibility of developing OLs to injury. Estrogen receptor (ER)–α and ER‐β are both expressed in OLs. We examined the effect of 17β‐estradiol on oxygen‐glucose deprivation and oxidative stress–induced cell death in rat pre‐OLs in vitro and on hypoxic‐ischemic brain injury in vivo. Pre‐OLs in culture were subjected to oxygen‐glucose deprivation (OGD) or glutathione depletion in the presence or absence of 17β‐estradiol. LDH release, the Alamar blue assay, and phase‐contrast microscopy were used to assess cell viability. Hypoxic‐ischemic injury was generated in 6‐day‐old rats (P6) by unilateral carotid ligation and hypoxia (6% O2 for 1 hr). Rat pups received one intraperitoneal injection of 300 or 600 μg/kg 17β‐estradiol or vehicle 12 hr prior to the surgical procedure. Injury was assessed by myelin basic protein (MBP) immunocytochemistry at P10. 17β‐Estradiol produced significant protection against OGD‐induced cell death in primary OLs (EC50 = 1.3 ± 0.46 × 10−9 M) and against oxidative stress. Moreover, 17β‐estradiol attenuated the loss of MBP labeling in P10 pups ipsilateral to the carotid ligation. These results suggest a potential role for estrogens in attenuation of hypoxic‐ischemic and oxidative injury to developing OLs and in the prevention of periventricular leukomalacia. © 2009 Wiley‐Liss, Inc.
Detection of localized retinal malfunction in retinal degeneration model using a multielectrode array system
Authors: Homma Kohei , Osakada Fumitaka , Hirami Yasuhiko , Jin Zi‐Bing , Mandai Michiko , Takahashi Masayo 
Published: February 2009

AbstractLight stimulation inhibits the retinal dark current through phototransduction signals in the photoreceptors. Electroretinography (ERG) detects the blockage of the dark current as the a‐wave of the ERG. However, standard ERGs represent the summed neural activity of the retina, and information on localized functions cannot be obtained. In this study, we used a multielectrode array (MEA) system and directly recorded the focal activities of the photoreceptors of the retina. Retinas were isolated from dark‐adapted rodents and were draped over the electrode array with vitreal surface of the retina on the electrode array. After light stimulation, negative waves were recorded from each electrode. Adding aminobutyric acid, a selective agonist of mGluR6 expressed on ON‐bipolar cells, to the media did not block the generation of the responses. The amplitude of the response increased with increasing retinal development. When the retina was locally injured, light‐elicited responses were diminished only in the injured areas of the retina. Retinas isolated from rats given N‐methyl‐N‐nitrosourea (MNU) were also tested. In central retinas of MNU‐treated rats, the responses were progressively decreased following injection of MNU. In contrast, in the peripheral retinas, amplitude of the responses was relatively retained, consistent with the retinal thickness observed by immunohistochemistry. In conclusion, light‐evoked responses were recorded with the MEA system. The MEA system was useful for detecting subtle and focal activation of photoreceptors. This spatial information should be valuable in investigating local functional recovery in therapeutically treated areas, such as in gene transfer or cell transplantation. © 2009 Wiley‐Liss, Inc.
Biostratigraphic and aminostratigraphic constraints on the age of the Middle Pleistocene glacial succession in north Norfolk, UK
Authors: Preece Richard C. , Parfitt Simon A. , Coope G. Russell , Penkman Kirsty E. H. , Ponel Philippe , Whittaker John E. 
Published: February 2009

AbstractConsiderable debate surrounds the age of the Middle Pleistocene glacial succession in East Anglia following some recent stratigraphical reinterpretations. Resolution of the stratigraphy here is important since it not only concerns the glacial history of the region but also has a bearing on our understanding of the earliest human occupation of north‐western Europe. The orthodox consensus that all the tills were emplaced during the Anglian (Marine Isotope Stage (MIS) 12) has recently been challenged by a view assigning each major till to a different glacial stage, before, during and after MIS 12. Between Trimingham and Sidestrand on the north Norfolk coast, datable organic sediments occur immediately below and above the glacial succession. The oldest glacial deposit (Happisburgh Till) directly overlies the ‘Sidestrand Unio‐bed’, here defined as the Sidestrand Hall Member of the Cromer Forest‐bed Formation. Dating of these sediments therefore has a bearing on the maximum age of the glacial sequence. This paper reviews the palaeobotany and describes the faunal assemblages recovered from the Sidestrand Unio‐bed, which accumulated in a fluvial environment in a fully temperate climate with regional deciduous woodland. There are indications from the ostracods for weakly brackish conditions. Significant differences are apparent between the Sidestrand assemblages and those from West Runton, the type site of the Cromerian Stage. These differences do not result from contrasting facies or taphonomy but reflect warmer palaeotemperatures at Sidestrand and a much younger age. This conclusion is suggested by the higher proportion of thermophiles at Sidestrand and the occurrence of a water vole with unrooted molars (Arvicola) rather than its ancestor Mimomys savini with rooted molars. Amino acid racemisation data also indicate that Sidestrand is significantly younger than West Runton. These data further highlight the stratigraphical complexity of the ‘Cromerian Complex’ and support the conventional view that the Happisburgh Till was emplaced during the Anglian rather than the recently advanced view that it dates from MIS 16. Moreover, new evidence from the Trimingham lake bed (Sidestrand Cliff Formation) above the youngest glacial outwash sediments (Briton's Lane Formation) indicates that they also accumulated during a Middle Pleistocene interglacial – probably MIS 11. All of this evidence is consistent with a short chronology placing the glacial deposits within MIS 12, rather than invoking multiple episodes of glaciation envisaged in the ‘new glacial stratigraphy’ during MIS 16, 12, 10 and 6. Copyright © 2009 John Wiley & Sons, Ltd.
Microcolumn LC enantioseparation of chiral compounds using diol silica gel functionalized with vancomycin crystalline degradation products
Authors: Gholami Morteza , Ghassempour Alireza , Alizadeh Reza , Aboul‐Enein Hassan Y. 
Published: February 2009

AbstractVancomycin crystalline degradation products (CDPs) have been introduced as one of the newest and most interesting derivatives of vancomycin for enantiomer separation of a wide variety of chiral compounds. In this attempt, a chiral stationary phase (CSP) has been prepared using diol silica gel based on vancomycin CDPs which led to a new chiral selector with new functionality of functional groups on a microcolumn LC. Different kinds of mobile phases were examined to realize the behavior of the chiral selector in separation of atropine, fluoxetine, amlodipine, mandelic acid, alanine, and phenylalanine which were separated successfully on this column. Good results were obtained by using a polar mobile phase containing water, methanol, and acid additives for separation of chiral acidic compounds and amino acid samples. Considerable results were obtained for analysis of basic compounds by using polar organic mobile phase (POP) containing methanol, acid and base additives. These results can be associated with the presence of the carboxylic acid groups present in new CSP by using a diol silica gel.
Multi‐mycotoxin analysis in complex biological matrices using LC‐ESI/MS: Experimental study using triple stage quadrupole and LTQ‐Orbitrap
Authors: Herebian Diran , Zühlke Sebastian , Lamshöft Marc , Spiteller Michael 
Published: February 2009

AbstractIn the present study, we report the application of LC‐MS based on two different LC‐MS systems to mycotoxin analysis. The mycotoxins were extracted with an ACN/water/acetic acid mixture and directly injected into a LC‐MS/MS system without any dilution procedure. First, a sensitive and reliable HPLC‐ESI‐MS/MS method using selected reaction monitoring on a triple quadrupole mass spectrometer (TSQ Quantum Ultra AM) has been developed for determining 32 mycotoxins in crude extracts of wheat and maize. This method was operated both in positive and in negative ionization modes in two separate chromatographic runs. The method was validated by studies of spiked recoveries, linearity, matrix effect, intra‐assay precision and sensitivity. Further, we have developed and evaluated a method based on accurate mass measurements of extracted target ions in full scan mode using micro‐LC‐LTQ‐Orbitrap as a tool for fast quantitative analysis. Both instruments exhibited very high sensitivity and repeatability in positive ionization mode. Coupling of micro‐LC to Orbitrap technology was not applicable to the negatively ionizable compounds. The LC triple quadrupole MS method has proved to be stable in quantitation, as it is with respect to the matrix effects of grain samples.
Generation of quantum‐entangled twin photons by waveguide nonlinear‐optic devices
Authors: Suhara T. 
Published: February 2009

AbstractThis paper reviews the quasi‐phase‐matched (QPM) waveguide nonlinear‐optic device technologies for generation of quantum‐entangled twin photons indispensable for quantum‐information techniques. After a brief introduction to the concept of entanglement, quantum theory analysis of twin‐photon generation (TPG) is outlined to clarify the properties of twin photons. Then, methods for entangled‐photon generation are discussed. Practical design and theoretical performances of LiNbO3 waveguide QPM TPG devices, as well as the fabrication techniques, are described. Finally, experimental demonstrations of polarization‐entangled twin‐photon generation by waveguide Type‐I and Type‐II QPM TPG devices are presented.
Edge symbolic structures of second generation
Authors: Calvo D. , Schulze B.‐W. 
Published: February 2009

AbstractOperators on a manifold with (geometric) singularities are degenerate in a natural way. They have a principal symbolic structure with contributions from the different strata of the configuration. We study the calculus of such operators on the level of edge symbols of second generation, based on specific quantisations of the corner‐degenerate interior symbols, and show that this structure is preserved under composition (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asymptotic analysis of solutions to parabolic systems
Authors: Kozlov Vladimir , Langer Mikael , Rand Peter 
Published: February 2009

AbstractWe study asymptotics as t → ∞ of solutions to a linear, parabolic system of equations with time‐dependent coefficients in Ω × (0, ∞), where Ω is a bounded domain. On ∂ Ω × (0, ∞) we prescribe the homogeneous Dirichlet boundary condition. For large values of t, the coefficients in the elliptic part are close to time‐independent coefficients in an integral sense which is described by a certain function κ (t). This includes in particular situations when the coefficients may take different values on different parts of Ω and the boundaries between them can move with t but stabilize as t → ∞. The main result is an asymptotic representation of solutions for large t. As a corollary, it is proved that if κ ∈ L1(0, ∞), then the solution behaves asymptotically as the solution to a parabolic system with time‐independent coefficients (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A maximum modulus estimate for solutions of the Navier–Stokes system in domains of polyhedral type
Authors: Maz'ya V. , Rossmann J. 
Published: February 2009

AbstractThe authors prove a maximum modulus estimate for solutions of the stationary Navier–Stokes system in bounded domains of polyhedral type (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bounded H∞‐calculus for pseudo‐differential Douglis–Nirenberg systems of mild regularity
Authors: Denk Robert , Saal Jürgen , Seiler Jörg 
Published: February 2009

AbstractWe consider pseudo‐differential Douglis–Nirenberg systems on ℝn with components belonging to the standard Hörmander class S1,δ *(ℝn × Rn ), 0 ≤ δ < 1. Parameter‐ellipticity with respect to a subsector Λ ⊂ ℂ is introduced and shown to imply the existence of a bounded H∞‐calculus in suitable scales of Sobolev, Besov, and Hölder spaces. We also admit non pseudo‐differential perturbations. Applications concern systems with coefficients of mild Hölder regularity and the generalized thermoelastic plate equations (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The essential spectrum of an operator arising in 2‐dimensional magneto‐hydrodynamics
Authors: Faierman M. , Mennicken R. 
Published: February 2009

AbstractDescloux and Geymonat considered a model problem for a plasma in a toroidal configuration and conjectured that the essential spectrum has an explicitly given band structure. This conjecture was recently proved by Faierman, Mennicken, and Möller by employing an operator matrix representation of the problem. In this paper we discuss the behaviour of the essential spectrum under a perturbation of the original problem (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Gevrey solvability and regularity
Authors: Petronilho Gerson 
Published: February 2009

AbstractIn this paper we study global C∞ and Gevrey solvability for a class of sublaplacian defined on the torus T3. We also prove Gevrey regularity for a class of solutions of certain operators that are globally C∞ hypoelliptic in the N ‐dimensional torus (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The duration of the motor response to apomorphine boluses is conditioned by the length of a prior infusion in Parkinson's disease
Authors: Vaamonde Julia , Flores José M. , Weisser Roberto , Ibañez Ramón , Obeso José A. 
Published: February 2009

Abstract“Pulsatile” administration of levodopa has been invocated a relevant factor for motor fluctuations in Parkinson's disease (PD). We studied dopaminergic sensitivity to apomorphine in 10 parkinsonian patients with motor fluctuations. Patients were tested as follows: the minimal effective dose of apomorphine (MED‐1) was administered in the morning to induce anonresponse. Fifteen minutes after this motor response had disappeared, an apomorphine infusion was initiated and maintained to ensureonperiods of three different durations on different days. Infusion lasted for ∼30, 60 and 90 minutes. Subsequently, the infusion was stopped, and after 15 minutes in theoffstate, a second bolus of apomorphine (MED‐2) was given. The mean infusion doses were 49.2 ± 5.4, 108.4 ± 10.3, and 150 ± 8.2 mg. These elicitedonperiods of 48.2 ± 4.1, 110 ± 4.5, and 195 ± 3.8 minutes. The MED‐2 elicitedonresponses with a duration of 30 ± 4.5, 18.4 ± 3.2, and 11.2 ± 4.1 minutes. The duration of theonresponse induced by the apomorphine infusions correlated inversely (P< 0.01) with theoninduced by the MED‐2 of apomorphine. Our findings indicate that a continuous dopaminergic stimulus may induce pharmacodynamic changes associated with tolerance in PD patients. © 2009 Movement Disorder Society
Contrast sensitivity in Parkinson's disease patients with subthalamic nucleus deep brain stimulation
Authors: Chou Kelvin L. , Amick Melissa M. , Gagner Margaret 
Published: February 2009

AbstractThis study examined whether deep brain stimulation (DBS) would affect the contrast sensitivity (CS) curve in patients with PD. CS was tested in 12 nondemented PD patients treated with bilateral subthalamic nucleus DBS on and off stimulation and medications. Neither stimulation condition (on vs. off) nor medications altered CS performance in this group of patients. However, collapsed across conditions, patients with bipolar stimulation in this study had significantly poorer CS at higher spatial frequencies (12 and 18 cycles per degree) than patients with monopolar stimulation. This suggests that CS deficits in PD may possibly be influenced by DBS polarity and merits further study. © 2009 Movement Disorder Society
Botulinum neurotoxins for post‐stroke spasticity in adults: A systematic review
Authors: Elia Antonio Emanuele , Filippini Graziella , Calandrella Daniela , Albanese Alberto 
Published: February 2009

AbstractThe aim of this systematic review was to determine whether botulinum neurotoxin (BoNT) reduce spasticity or improve function in adult patients after stroke. Eleven double‐blind randomized placebo‐controlled trials met inclusion criteria. They encompassed 782 patients, 767 (98%) of whom received BoNT/A, and 15 (2%) BoNT/B. Most studies used the Ashworth scale as primary outcome measure. Differences between treated and control groups were assessed as categorical or continuous comparisons. The overall effect on upper limb spasticity was in favor of BoNT/A. A significantly higher number of patients had a reduction of upper limb spasticity at 4‐week and 8‐week evaluations in the treatment group compared with placebo. Mean changes in joint spasticity revealed improvement 3 to 6 weeks and 9 to 12 weeks after treatment. There were insufficient data to establish BoNT/A efficacy on lower limb spasticity or the effect of BoNT/B on the upper and lower limbs. Because of inconsistency and heterogeneity of the available data, it was not possible to perform a meta‐analysis on disability and patients' reported outcomes. There was an overlapping safety profile between the treatment and the placebo groups. BoNT/A reduces upper limb spasticity in patients post‐stroke, but the improvement in functional ability remains to be established. This gap needs to be filled by new studies to assess the effect of BoNT in the context of multidisciplinary patient management. © 2009 Movement Disorder Society
Investigation of the correlations between 19F and 1H NMR signals for various mono‐ and di‐substituted octafluoro[2.2]paracyclophanes
Authors: Roche Alex J. , Marchione Alexander A. 
Published: February 2009

AbstractA selection of mono‐ and pseudo ortho di‐substituted octafluoro[2.2]paracyclophane derivatives were analyzed using 19F‐1H HOESY, 1H COSY and 19F COSY techniques. This resulted in the unambiguous assignment of the 19F and 1H NMR resonances, and also revealed interesting solvent effects and noteworthy coupling patterns for various JHH, JHF, and JFF interactions, including observable through bond 7JFF and 8JFF couplings. For the four mono‐substituted derivatives, the assignments were achieved through the combination of 19F‐1H HOESY, 1H COSY and 19F COSY techniques. The C2 symmetry of the six pseudo ortho di‐substituted derivatives that were examined produced simplified spectra, and careful inspection of the characteristic 1H coupling patterns led to the assignment of 1H signals. Therefore only 19F‐1H HOESY experiments were required to complete the assignments for those molecules. Refinements and alternative strategies for previous protocols are presented for the molecules that were less responsive to nuclear Overhauser effect (nOe) experiments. Copyright © 2009 John Wiley & Sons, Ltd.
Statistical inverse analysis based on genetic algorithm and principal component analysis: Method and developments using synthetic data
Authors: Levasseur S. , Malecot Y. , Boulon M. , Flavigny E. 
Published: February 2009

AbstractThis study concerns the identification of parameters of soil constitutive models from geotechnical measurements by inverse analysis. To deal with the non‐uniqueness of the solution, the inverse analysis is based on a genetic algorithm (GA) optimization process. For a given uncertainty on the measurements, the GA identifies a set of solutions. A statistical method based on a principal component analysis (PCA) is, then, proposed to evaluate the representativeness of this set. It is shown that this representativeness is controlled by the GA population size for which an optimal value can be defined. The PCA also gives a first‐order approximation of the solution set of the inverse problem as an ellipsoid. These developments are first made on a synthetic excavation problem and on a pressuremeter test. Some experimental applications are, then, studied in a companion paper, to show the reliability of the method. Copyright © 2009 John Wiley & Sons, Ltd.
A numerical method for the study of shear band propagation in soft rocks
Authors: Castelli Marta , Allodi Andrea , Scavia Claudio 
Published: February 2009

AbstractThis paper investigates the possibility of interpreting progressive shear failure in hard soils and soft rocks as the result of shear propagation of a pre‐existing natural defect. This is done through the application of the principles of fracture mechanics, a slip‐weakening model (SWM) being used to simulate the non‐linear zone at the tips of the discontinuity. A numerical implementation of the SWM in a computation method based on the boundary element technique of the displacement discontinuity method (DDM) is presented. The crack and the non‐linear zone at the advancing tip are represented through a set of elements, where the displacement discontinuity (DD) in the tangential direction is determined on the basis of a friction law. A residual friction angle is assumed on the crack elements. Shear resistance decreases on elements in the non‐linear zone from a peak value at the tip, which is characteristic of intact material, to the residual value. The simulation of a uniaxial compressive test in plane strain conditions is carried out to exemplify the numerical methodology. The results emphasize the role played by the critical DD on the mechanical behaviour of the specimen. A validation of the model is shown through the back analysis of some experimental observations. The results of this back analysis show that a non‐linear fracture mechanics approach seems very promising to simulate experimental results, in particular with regards to the shear band evolution pattern. Copyright © 2009 John Wiley & Sons, Ltd.