bluuebunny/crossref_metadata_2025_split huggingface dataset:
Competitive AMPA receptor antagonists
Authors: Catarzi Daniela , Colotta Vittoria , Varano Flavia 
Published: August 2006

AbstractGlutamic acid (Glu) is the major excitatory neurotransmitter in the mammalian central nervous system (CNS) where it is involved in the physiological regulation of different processes. It has been well established that excessive endogenous Glu is associated with many acute and chronic neurodegenerative disorders such as cerebral ischaemia, epilepsy, amiotrophic lateral sclerosis, Parkinson's, and Alzheimer's disease. These data have consequently added great impetus to the research in this field. In fact, many Glu receptor antagonists acting at theN‐methyl‐D‐aspartic acid (NMDA), 2‐amino‐3‐(3‐hydroxy‐5‐methylisoxazol‐4‐yl)propionic acid (AMPA), and/or kainic acid (KA) receptors have been developed as research tools and potential therapeutic agents. Ligands showing competitive antagonistic action at the AMPA type of Glu receptors were first reported in 1988, and the systemically active 2,3‐dihydroxy‐6‐nitro‐7‐sulphamoyl‐benzo[f]quinoxaline (NBQX) was first shown to have useful therapeutic effects in animal models of neurological disease in 1990. Since then, the quinoxaline template has represented the backbone of various competitive AMPA receptor antagonists belonging to different classes which had been developed in order to increase potency, selectivity and water solubility, but also to prolong the “in vivo” action. Compounds that present better pharmacokinetic properties and less serious adverse effects with respect to the others previously developed are undergoing clinical evaluation. In the near future, the most important clinical application for the AMPA receptor antagonists will probably be as neuroprotectant in neurodegenerative diseases, such as epilepsy, for the treatment of patients not responding to current therapies. The present review reports the history of competitive AMPA receptor antagonists from 1988 up to today, providing a systematic coverage of both the open and patent literature. © 2006 Wiley Periodicals, Inc.
Percent infarct mapping: An R1‐map‐based CE‐MRI method for determining myocardial viability distribution
Authors: Surányi Pál , Kiss Pál , Brott Brigitta C. , Simor Tamás , Elgavish Ada , Ruzsics Balázs , Saab‐Ismail Nada H. , Elgavish Gabriel A. 
Published: August 2006

AbstractViability detection is crucial for the management of myocardial infarction (MI). Signal intensity (SI)‐based MRI methods may overestimate infarct size in vivo. In contrast to SI, the longitudinal relaxation‐rate enhancement (ΔR1) is an intrinsic parameter that is linearly proportional to the concentration of contrast agent (CA). Determining ΔR1 in the presence of an infarct‐avid persistent CA (PCA) allows determination of the per‐voxel percentage of infarcted tissue. Introduced here is a ΔR1‐based CE‐MRI method, termed percent infarct mapping (PIM), for quantifying myocardial viability following delayed PCA accumulation. In a canine MI model (N = 6), PIMs were generated using a persistent CA (PCA) and validated using triphenyltetrazolium‐chloride (TTC) histochemistry. Voxel‐by‐voxel R1 maps of the entire left ventricle (LV) were generated 24 and 48 hr after PCA administration using inversion recovery (IR) with multiple inversion times (TIs). PI values were calculated voxel by voxel. Significant correlations (P < 0.01, R = 0.97) were obtained for PI per slice (PIS) determined using PIM vs. corresponding TTC‐based values. Median deviations of PIS with PIM from that with TTC were only 1.01% and –0.53%, at 24 hr and 48 hr. Median deviations from the true infarction fraction (IF) were 1.23% and 0.49% of LV at 24 hr and 48 hr, respectively. No significant difference was found between PIM24 hr and PIM48 hr. ΔR1‐based PIM is an accurate and reproducible method for quantifying myocardial viability distribution, and thus enhances the clinical utility of CE‐MRI. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Proton spectral editing for discrimination of lactate and threonine 1.31 ppm resonances in human brain in vivo
Authors: Choi Changho , Coupland Nicholas J. , Kalra Sanjay , Bhardwaj Paramjit P. , Malykhin Nikolai , Allen Peter S. 
Published: August 2006

AbstractA single‐voxel proton NMR J‐difference editing method for discriminating between the 1.31 ppm resonances of lactate (Lac) and threonine (Thr) in human brain in vivo at 3 T is reported. One double‐band and two triple‐band Gaussian 180° RF pulses, all with a bandwidth of 15 Hz, were employed within an adiabatic‐refocused double‐echo localization sequence to induce the target signals of Lac and Thr and simultaneously acquire a creatine singlet in each subscan. The optimum echo time and the editing efficiency were obtained by numerical analysis of the filtering performance. The Lac and Thr signals were extracted, without lipid contamination, from three subspectra. Using the calculated yields, the concentrations of Lac and Thr in the human occipital cortex were estimated to be 0.47 ± 0.07 and 0.56 ± 0.06 mM (mean ± SD, N = 7), respectively, with reference to Cr at 8 mM. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Amide proton transfer imaging of human brain tumors at 3T
Authors: Jones Craig K. , Schlosser Michael J. , van Zijl Peter C.M. , Pomper Martin G. , Golay Xavier , Zhou Jinyuan 
Published: August 2006

AbstractAmide proton transfer (APT) imaging is a technique in which the nuclear magnetization of water‐exchangeable amide protons of endogenous mobile proteins and peptides in tissue is saturated, resulting in a signal intensity decrease of the free water. In this work, the first human APT data were acquired from 10 patients with brain tumors on a 3T whole‐body clinical scanner and compared with T1‐ (T1w) and T2‐weighted (T2w), fluid‐attenuated inversion recovery (FLAIR), and diffusion images (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)). The APT‐weighted images provided good contrast between tumor and edema. The effect of APT was enhanced by an approximate 4% change in the water signal intensity in tumor regions compared to edema and normal‐appearing white matter (NAWM). These preliminary data from patients with brain tumors show that the APT is a unique contrast that can provide complementary information to standard clinical MRI measures. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Reduction of reconstruction time for time‐resolved spiral 3D contrast‐enhanced magnetic resonance angiography using parallel computing
Authors: Kressler Bryan , Spincemaille Pascal , Prince Martin R. , Wang Yi 
Published: August 2006

AbstractTime‐resolved 3D MRI with high spatial and temporal resolution can be achieved using spiral sampling and sliding‐window reconstruction. Image reconstruction is computationally intensive because of the need for data regridding, a large number of temporal phases, and multiple RF receiver coils. Inhomogeneity blurring correction for spiral sampling further increases the computational work load by an order of magnitude, hindering the clinical utility of spiral trajectories. In this work the reconstruction time is reduced by a factor of >40 compared to reconstruction using a single processor. This is achieved by using a cluster of 32 commercial off‐the‐shelf computers, commodity networking hardware, and readily available software. The reconstruction system is demonstrated for time‐resolved spiral contrast‐enhanced (CE) peripheral MR angiography (MRA), and a reduction of reconstruction time from 80 min to 1.8 min is achieved. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Steady state of echo–shifted sequences with radiofrequency phase cycling
Authors: Ganter Carl 
Published: August 2006

AbstractDue to a delayed echo–formation, echo–shifted gradient echo sequences (ES–GRE) allow for an enhanced T2*–weighting at short repetition times. While they are in use with and without RF spoiling, analytical solutions are only known for the latter. The signal formation in the former could only be assessed in approximative form, so far. In this article an exact analytical solution is presented for TR–periodic ES–GRE sequences with RF phase cycling. Besides providing a better numerical performance, it should be useful for systematic sequence development. The relation to recent approximative solutions is discussed. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Motor unit number estimation predicts disease onset and survival in a transgenic mouse model of amyotrophic lateral sclerosis
Authors: Shefner Jeremy M. , Cudkowicz Merit , Brown Robert H. 
Published: August 2006

AbstractMotor unit number estimation (MUNE) has proved useful in predicting rate of progression and survival in patients with amyotrophic lateral sclerosis (ALS). In animal models, it has demonstrated physiological effects of experimental medications that were not evident behaviorally. We sought to determine more specifically what aspects of function and survival that MUNE could predict in the G93A transgenic mouse model of ALS. Transgenic mice were examined in two distinct treatment studies, neither of which showed an effect of drug on survival, behavioral measures, or MUNE. MUNE was performed using a modification of the incremental stimulation method by stimulating the sciatic nerve at the sciatic notch, and recording with a circumferential surface electrode around the ipsilateral distal hindlimb. Both limbs were studied and the results averaged. MUNE was performed longitudinally on all animals from near onset to premorbid state. Each study was evaluated separately. For both studies, MUNE at initial study correlated significantly with behavioral determination of disease onset, and MUNE slope from initial to final study correlated significantly with disease duration, as measured from onset to time of death. However, the final MUNE value did not correlate with survival. Thus, in two studies involving animals with quite different disease courses, initial MUNE effectively predicted symptom onset and MUNE slope predicted survival. This suggests that MUNE has potential efficacy as a useful functional outcome measure in both animal and human studies of ALS. Muscle Nerve, 2006
High‐repetition cyclic loading is a risk factor for a lumbar disorder
Authors: Navar Daniel , Zhou Bing‐He , Lu Yun , Solomonow Moshe 
Published: August 2006

AbstractEpidemiological data suggest that prolonged exposure to cyclic lumbar flexion elicits a chronic neuromuscular disorder and disability in workers. This study provides a physiological and biomechanical assessment of various repetitions of cyclic lumbar flexion sessions as a risk factor for development of an acute neuromuscular disorder. An in vivo feline model was subjected to 10 minutes of cyclic (0.25‐HZ) loading, followed by a 10‐minute rest period, repeated three times in one experimental group, six times in a second group, and nine times in the third group, followed by rest for 7 hours. Displacement of the lumbar viscoelastic tissue and reflex electromyographic (EMG) activity from the lumbar multifidus muscle were monitored. Creep developed and accumulated during each load/rest period and partially recovered during the subsequent rest. Loading periods were characterized by a decrease in reflex EMG activity with superimposed spasms. In the 7‐hour recovery period, initial hyperexcitability was present in all groups, whereas only the six‐ and nine‐repetition groups displayed significant delayed hyperexcitability, indicating the presence of acute inflammation. The mathematical model developed fit the data reasonably well, as the R2 values were generally near 0.90. It was concluded that the resulting delayed muscular hyperexcitability constitutes an acute neuromuscular disorder associated with exposure to many repetitions of cyclic lumbar flexion. The acute disorder can become chronic if not allowed sufficient rest to resolve itself. Workers engaged in cyclic lumbar flexion (e.g., loading/unloading, assembly workers) should avoid long‐term exposure in order to prevent the development of a chronic neuromuscular condition known as cumulative trauma disorder. Muscle Nerve, 2006
Formation of Si and Ge quantum structures by laser‐induced etching
Authors: Mavi H. S. , Prusty Sudakshina , Kumar Manoj , Kumar Rajesh , Shukla A. K. , Rath S. 
Published: August 2006

AbstractQuantum structures were fabricated by immersing a crystalline silicon (Si) or germanium (Ge) wafer in hydrofluoric acid followed by laser‐induced etching with a laser photon energy of 2.41 eV. Atomic force microscopy (AFM) investigations of Si(100) etched samples reveal a complex surface morphology with pits from the top view and pillar‐like structures from the three‐dimensional view of the pit wall. For Ge(111) laser‐etched samples, AFM shows parallel wall‐type structures and Ge quantum structures on the surface of the walls. Laser‐induced etching of Ge is reported for the first time. Observation of photoluminescence spectra from both samples confirms the presence of quantum confined structures. Line‐shape analysis of Raman spectra is used to estimate the size of the quantum structures. The sizes of nanoparticles can be controlled by the laser power density and irradiation time for etching. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Color centers in Yb:YAG crystals grown by temperature‐gradient techniques
Authors: Dong Yongjun , Xu Jun , Zhou Guoqing , Zhao Guangjun , Su Liangbi , Xu Xiaodong , Li Hongjun , Si JiLiang , Qian Xiaobo , Li Xiaoqing , Shen Jun 
Published: August 2006

AbstractYb:YAG (Yb:Y3Al5O12) crystals have been grown by temperature‐gradient techniques (TGT) and their color centers and impurity defects were investigated by means of gamma irradiations and thermal treatment. Two color centers located at 255 and 290 nm were observed in the as‐grown TGT‐Yb:YAG. Analysis shows that the 255 nm band may be associated with Fe3+ ions. Absorption intensity changes of the 290 nm band after gamma irradiation and thermal treatment indicate that this band may be associated with oxygen‐vacancy defects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Perovskite phase formation, microstructure and improvement of dielectric properties in iron‐containing ferroelectrics
Authors: Fang Bijun , Geng Baoyou , Wei Xianwen , Shan Yuejin , Tezuka Keitaro , Imoto Hideo 
Published: August 2006

AbstractPure perovskite‐phase lead iron scandium niobate, Pb(Fe1/4Sc1/4Nb1/2)O3 (PFScN), ceramics have been prepared by a conventional solid‐state reaction method via a B‐site oxide mixing route. Although synthesis conditions have been tailored to optimization, strong frequency dispersion of the dielectric properties cannot be improved by modifying ceramic processing, which is considered as correlating to the nature of iron‐containing ferroelectrics. Sintering in an O2 atmosphere and MnO2 and Li2CO3 dopings tend to decrease the dielectric loss of the iron‐containing dielectrics. The strong frequency dispersion of the dielectric response and the abnormally recurrent increase of the dielectric constant and loss in the paraelectric region are correspondingly suppressed. This improvement of dielectric properties in the iron‐containing ferroelectrics is interpreted by an electron compensation mechanism, in which the generation of donor electrons is based on different ionization paths. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of annealing atmosphere on oxygen precipitation and formation of denuded zone in Czochralski silicon wafer
Authors: Cui Can , Yang Deren , Ma Xiangyang , Fan Ruixin , Que Duanlin 
Published: August 2006

AbstractIn this paper, the effect of annealing atmosphere on oxygen precipitation and formation of denuded zone (DZ) in Czochralski (CZ) silicon has been investigated. It was revealed that the high‐temperature annealings in various atmospheres resulted in almost identical oxygen outdiffusion length but different widths of DZ in the silicon wafers. It was confirmed that the high‐temperature annealing in nitrogen atmosphere induced a high concentration of vacancies in silicon to enhance oxygen precipitation, while the annealing in oxidizing atmosphere or steam‐mixed atmosphere induced a high concentration of silicon self‐interstitials to retard oxygen precipitation. Moreover, it was confirmed that the steam mixed into the nitrogen atmosphere could suppress the indiffusion of nitrogen atoms. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermoelectric properties of higher manganese silicide films with addition of carbon
Authors: Hou Q. R. , Zhao W. , Zhang H. Y. , Chen Y. B. , He Y. J. 
Published: August 2006

AbstractPolycrystalline higher manganese silicide (MnSi1.73, HMS) films with addition of carbon were prepared on thermally oxidized silicon substrates by magnetron sputtering. A carbon cap layer was used as the doping source. Both the Seebeck coefficient and the resistivity were strongly dependent on the amount of carbon added to the films. When the thickness ratio of carbon to manganese was about 17%, the Seebeck coefficient and resistivity at room temperature were about 35 μV/K and 4.45 × 10–3 Ω cm, respectively. By reducing the thickness ratio to about 3%, the Seebeck coefficient and resistivity at room temperature increased to 107 μV/K and 18 × 10–3 Ω cm, respectively. With addition of carbon, both the maximum value of the Seebeck coefficient and the temperature at which the maximum occurred increased. Several shallow (0.028–0.085 eV) and deep (0.106–0.299 eV) energy levels were observed from the curves of the resistivity versus temperature. The activation energies of 0.845 and 1.11 eV were consistent with the reported energy band gaps for higher manganese silicide. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
“As‐cast” microstructure investigation of two iron aluminides
Authors: Schön Cláudio Geraldo , Scuracchio Bruno Geoffroy 
Published: August 2006

AbstractThe “as‐cast” microstructure of Fe–30Al–6Cr and Fe–30Al–10Ti high purity alloys was investigated using Electron Backscatter Diffraction. The first alloy is characterized by a highly textured columnar grain microstructure with large grains, while the second is characterized by an equiaxed grain microstructure with small grains and a random texture. These differences are discussed with regard to the higher reactivity of Ti compared with Cr, leading to nanometric nitride or oxide, which may act as sites for heterogeneous nucleation, and the ordered state of the BCC phase in equilibrium with the liquid during solidification and its effect upon dendrite growth kinetics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and acoustic investigations of calcium borate glasses
Authors: Manupriya  , Thind K. S. , Sharma G. , Rajendran V. , Singh K. , Gayathri Devi A. V. , Aravindan S. 
Published: August 2006

AbstractAcoustic and structural properties of x CaO · (1–x ) B2O3 (0.2 ≤ x ≥ 0.7) glass system have been studied at ambient temperature. The ultrasonic velocity and attenuation for different compositions of calcium borate glasses were measured at 5 MHz at room temperature (303 K) using a pulse echo overlap method. The elastic moduli, Debye temperature, Poisson's ratio and other acoustic parameters have been obtained from experimental data. Fourier transform infrared spectroscopic analysis has been used to further support the results of acoustic studies. The results obtained indicate that the calcium oxide enters the glass network as a modifier by occupying the interstitial spaces in the network and by increasing the nonbridging oxygen atoms (NBOs). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and electrical transport of some Cd‐doped La0.67Sr0.33MnO3manganites
Authors: Venkataiah G. , Prasad V. , Venugopal Reddy P. 
Published: August 2006

AbstractA systematic investigation of cadmium‐doped manganites with compositional formula La0.67(Sr0.33–yCdy) MnO3(y= 0–0.33) has been undertaken mainly to understand their structural as well as their electrical transport behavior. The materials were prepared by the citrate‐gel route and were characterized by X‐ray diffraction (XRD). By analyzing the XRD data using the Rietveld refinement technique, it has been concluded that these materials have rhombohedral structure with R$ \bar 3 $c space group. It has been found that the ferro–paramagnetic transition temperature (TC) values decrease continuously with increasing Cd concentration, while the metal–insulator transition temperatures (TP1), except in the cases of two samples (withy= 0.066 and 0.132), are found to decrease. A qualitative explanation for the observed behavior is offered. With a view to understanding the conduction mechanism, electrical resistivity and thermopower measurements were carried out and the data were analyzed using various theoretical models. It has been concluded that the resistivity (ρ) data in the ferromagnetic metallic part (T<TP1) is in agreement withρ(T) =ρ0+ρ2T2+ρ4.5T4.5, indicating the importance of grain/domain boundary effects, electron–electron and two‐magnon scattering processes in the conduction mechanism, while, at high temperature (T>TP1), the paramagnetic insulating regime, the adiabatic small polaron model fits well, thereby indicating that polaron hopping might be responsible for the conduction mechanism. Finally, the low‐temperature thermopower (T<TP1) data were analyzed by considering the spin‐wave fluctuation (∼T4) in addition to the magnon scattering, whereas the high‐temperature (T>TP1) data were analyzed by Mott's equation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Feature Article: Hot phonons in GaN channels for HEMTs
Authors: Matulionis A. 
Published: August 2006

AbstractIn the Feature Article [1] a fluctuation technique is used to obtain the hot electron energy relaxation time (blue symbols in the cover picture) and the hot phonon lifetime (red) for a biased two‐dimensional channel in an AlGaN/AlN/GaN heterostructure as a function of the supplied electric power. The close proximity of red and blue symbols illustrates that the relaxation is mainly determined by the phonon conversion into other vibrational modes being able to drain the Joule heat out of the channel. The red inset shows the momenta of hot phonons launched by hot electrons. The green line presents the electron energy relaxation time obtained by Monte Carlo simulation for lightly doped GaN under the assumption that hot phonons are absent. A strong effect of hot phonons on the electron energy relaxation is evident.The author Arvydas Matulionis is Professor of Physics and head of the Fluctuation Research Laboratory of the Vilnius Semiconductor Physics Institute. He investigates hot electron fluctuations and other high electric field effects in semiconductor heterostructures for microwave electronics.The Editor's Choice “Anomalous charge relaxation in channels of pentacene‐based organic field‐effect transistors: a charge transient spectroscopy study” by I. Thurzo et al. [2] is also part of the present issue.
6th International Symposium on Blue Laser and Light Emitting Diodes (ISBLLED 2006), Montpellier, France, 15–19 May 2006
Authors: Duboz Jean‐Yves 
Published: August 2006

AbstractConference Reports are meant to offer an authoritative view on a recently held scientific meeting rather than a comprehensive list of the conference presentations. Authors are invited to describe what they feel were the most interesting contributions.The full Proceedings of ISBLLED 2006 will be published in phys. stat. sol. (a) and phys. stat. sol. (c) at the end of 2006.