bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accurate measurement of 1J(195Pt, 14N) in K[Pt(NH3)Cl3] by complete lineshape analysis
Authors: Gore Ernest S. 
Published: August 2002

AbstractBecause the 195Pt triplet due to coupling with 14N in K[Pt(NH3)Cl3] in D2O is significantly broadened, 1J(195Pt, 14N) determined from the peak separation is not exactly equal to the true coupling constant. It is shown that an accurate value can be determined by a complete lineshape analysis. However, the previously published equation for the lineshape of a spin‐½ nucleus bound to a spin‐1 nucleus is not valid in this case because the intrinsic linewidth of the 195Pt resonance cannot be ignored. A closed expression for the lineshape is given which accounts for the intrinsic linewidth and gives a value for 1J(195Pt, 14N) at 300 K of 235.3±0.2 Hz, in good agreement with the value, 234 Hz, calculated from the published value of 1J(195Pt, 15N) and significantly different than the value, 230.4±1.7 Hz, determined from the peak separation. The T1 of 14N was measured directly by the inversion‐recovery technique and compared with the values extracted from the lineshape. The lineshape T1 values were shown to be unreliable unless T1 ≪ T20, where 1&#38;sol;T20 is the intrinsic linewidth of 195Pt. Also observed was a deuterium isotope effect on the chemical shift of 195Pt of −2.7 ppm per deuteron bound to N and a temperature variation of 0.74 ppm K−1 for the 195Pt chemical shift. Copyright © 2001 John Wiley & Sons, Ltd.
Total assignment of the 1H and 13C NMR data for felodipine and its derivatives
Authors: Jung Jihyun , Kim Laehee , Lee Chang Sik , Cho Yoon Hwan , Ahn Seung‐Ho , Lim Yoongho 
Published: August 2002

AbstractThe 1H and 13C NMR data for felodipine and its derivatives were completely assigned. Felodipine has 3‐ethyl and 5‐methyl esters which make the 1,4‐dihydropyridine asymmetric. It is, however, difficult to distinguish 2,6‐dimethyl groups in the NMR spectra. With the help of NOESY and computer‐aided molecular modeling, these groups can be assigned. Whereas the 1,4‐dihydropyridine of felodipine is connected through a methine carbon to a dichlorophenyl ring, the aromatic pyridine of felodipine derivatives is connected through a quaternary carbon. As a result, the three‐dimensional conformations between the pyridine ring and the phenyl ring have important implications. Copyright © 2001 John Wiley & Sons, Ltd.
1H and 13C NMR structure determination of new sesquiterpene glycosides isolated from Pittosporum viridiflorum viridiflorum
Authors: Ramanandraibe Voahangy , Rakotovao Marcelle , Frappier François , Martin Marie‐Thérèse 
Published: August 2002

AbstractThe acetone extract of fresh leaves of Pittosporum viridiflorum viridiflorum afforded new sesquiterpene glycosides, 4‐O‐β‐D‐glucopyranosylgermacra‐1(10),5‐diene and its 6′‐O‐acetyl and 2′‐O‐acetyl derivatives, the structures of which were elucidated by NMR methods. Copyright © 2001 John Wiley & Sons, Ltd.
Connectivities in molecules by INADEQUATE: recent developments
Authors: Buddrus J. , Lambert J. 
Published: August 2002

AbstractThe INADEQUATE (Incredible Natural Abundance DoublE QUAntum Transfer Experiment) consists of a pulse sequence which eliminates the NMR signals from isolated spins (spin system A) displaying signals from coupled spins (spin system AX or higher spin systems). It is of great importance when applied to molecules with skeleton elements such as carbon, silicon or tungsten, all of which contain a small percentage of spin‐½ isotopes embedded in magnetically inactive isotopes. Analysis of the AX type spectra gives one‐bond and long‐range coupling constants (see compound 6) and, most important, the connectivity pattern of the skeleton atoms in molecules of unknown structure such as the carbon compounds 1 or 2, the silicon compound 3 or the lithium compound 4b. Unfortunately, INADEQUATE is rather insensitive, in the case of carbon only one out of 104 molecules gives the desired response. Efforts to reduce this drawback are described; recently, a remarkable step forward has been made by concentrating the four lines of an AX spin system to just two signals (see Fig. 2). Copyright © 2001 John Wiley & Sons, Ltd.
The 2‐imino‐1,3‐selenazolidine group bonded to phosphorus and silicon: a multinuclear magnetic resonance study
Authors: Bakhmutova Ekaterina V. , Cruz Alejandro , Ramirez‐Trejo Raúl , Contreras Rosalinda , Wrackmeyer Bernd 
Published: August 2002

AbstractA tris(imino)phosphane (3), its sulfide [3(S)], an iminodiphenylphosphane (4), and an iminotrimethylsilane (5), in all of which the imino group belongs to a pseudo‐ephedrine‐derived 2‐imino‐1,3‐selenazolidine ring, were prepared and studied by multinuclear magnetic resonance (1H, 13C, 15N, 29Si, 31P, 77Se NMR). By application of various 1D and 2D NMR techniques, NMR parameters such as the isotope induced chemical shifts 1Δ14/15N(31P) for 4, 1Δ14/15N(29Si) for 5, numerous coupling constants and chemical shifts could be obtained. The absolute sign of 1J(29Si,15N) (>0) was determined for 5. The largest values so far for 3J(77Se,31P) (198.0 Hz in 3 and 194.0 Hz in 4) were observed, and the absolute sign of these coupling constants 3J(77Se,31P) > 0 was determined, together with the signs of various other coupling constants involving 77Se or 31P. Copyright © 2001 John Wiley & Sons, Ltd.
Growth hormone inhibits apoptosis in in vitro produced bovine embryos
Authors: Kölle Sabine , Stojkovic Miodrag , Boie Gudrun , Wolf Eckhard , Sinowatz Fred 
Published: August 2002

AbstractGrowth hormone (GH) has recently been shown to exert distinct effects on the differentiation and metabolism of early embryos. Up to now, however, it is not clear whether GH is able to modulate apoptosis during early embryogenesis. Differential cell staining of 8‐day‐old bovine embryos cultured with 100 ng bovine recombinant GH (rbGH) per ml medium (synthetic oviduct fluid–polyvinylalcohol) demonstrated that GH significantly increased the number of inner cell mass (ICM) and trophectoderm cells in bovine expanded blastocysts. As shown by terminal deoxynucleotidyl transferase mediated dUTP labeling (TUNEL) supplementation of bGH decreased the percentage of 8‐day‐old embryos showing at least one apoptotic cell from 58 to 21%. The percentage of apoptotic cells in one blastocyst was significantly (P < 0.01) reduced from 4.6 to 1.1% by GH treatment. Incubation of the embryos with 150 mM vanillylnonanamide induced apoptosis in all embryos. Whereas in control embryos 14% of the embryonic cells were TUNEL‐positive, the percentage of apoptotic cells declined to 2.7% in the GH treated embryos. Expression of immunoreactive bcl‐2 in blastocysts was not affected by GH treatment. Synthesis of the bax protein which is known to promote apoptosis was reduced in embryos cultured with GH. Our results suggest that GH acts as survival factor during in vitro culture and reduces apoptosis by altering the bax to bcl‐2 ratio during early embryogenesis. Mol. Reprod. Dev. 61: 180–186, 2002. © 2002 Wiley‐Liss, Inc.
Origin and minimization of residual motion‐related artifacts in navigator‐corrected segmented diffusion‐weighted EPI of the human brain
Authors: Jiang Hangyi , Golay Xavier , van Zijl Peter C.M. , Mori Susumu 
Published: August 2002

AbstractMotion sensitivity in diffusion‐weighted imaging (DWI) can be effectively suppressed using single‐shot echo‐planar imaging (EPI). However, segmented (multishot) EPI is often used to increase resolution and reduce spatial distortions, which in turn increases susceptibility to brain motion. The sources of these residual motion artifacts in navigator‐echo‐corrected segmented EPI images of the brain were investigated. The results indicate that the dominant source of these artifacts is cardiac pulsation with occasional involuntary movement of the subject. The relationship between the cardiac cycle and motion artifacts shows that optimum timing for the data acquisition is possible. In addition it is shown that the effects of involuntary motion can be removed by swapping k‐space data between redundant datasets. Magn Reson Med 47:818–822, 2002. © 2002 Wiley‐Liss, Inc.
VD‐AUTO‐SMASH imaging
Authors: Heidemann Robin M. , Griswold Mark A. , Haase Axel , Jakob Peter M. 
Published: August 2002

AbstractRecently a self‐calibrating SMASH technique, AUTO‐SMASH, was described. This technique is based on PPA with RF coil arrays using auto‐calibration signals. In AUTO‐SMASH, important coil sensitivity information required for successful SMASH reconstruction is obtained during the actual scan using the correlation between undersampled SMASH signal data and additionally sampled calibration signals with appropriate offsets in k‐space. However, AUTO‐SMASH is susceptible to noise in the acquired data and to imperfect spatial harmonic generation in the underlying coil array. In this work, a new modified type of internal sensitivity calibration, VD‐AUTO‐SMASH, is proposed. This method uses a VD k‐space sampling approach and shows the ability to improve the image quality without significantly increasing the total scan time. This new k‐space adapted calibration approach is based on a k‐space–dependent density function. In this scheme, fully sampled low‐spatial frequency data are acquired up to a given cutoff‐spatial frequency. Above this frequency, only sparse SMASH‐type sampling is performed. On top of the VD approach, advanced fitting routines, which allow an improved extraction of coil‐weighting factors in the presence of noise, are proposed. It is shown in simulations and in vivo cardiac images that the VD approach significantly increases the potential and flexibility of rapid imaging with AUTO‐SMASH. Magn Reson Med 45:1066–1074, 2001. © 2001 Wiley‐Liss, Inc.
Rat lung MRI using low‐temperature prepolarized helium‐3
Authors: Kober Frank , Wolf Pierre‐Etienne , Vermeulen Gérard , Duhamel Guillaume , Lamalle Laurent , Leviel Jean‐Louis , Décorps Michel , Ziegler Anne 
Published: August 2002

AbstractThe purpose of this study was to evaluate the recently proposed technique of 3He prepolarization at low temperature and high field (Kober et al. Magn Reson Med 1999; 41:1084–1087) for fast imaging of the lung. Helium‐3 was cooled to 2.4 K in a magnetic field of 8 Tesla to obtain a polarization of 0.26%. The polarized 3He was warmed up to room temperature and transferred to a rat, with a final polarization of about 0.1%, large enough for acquiring a 3D image of the rat lung in 30 s. Magn Reson Med 45:1130–1133, 2001. © 2001 Wiley‐Liss, Inc.
Fast T1 mapping with volume coverage
Authors: Steinhoff S. , Zaitsev M. , Zilles K. , Shah N.J. 
Published: August 2002

AbstractFour different sequences which enable high‐resolution, multislice T1 relaxation‐time mapping are presented. All these sequences are based on the Look‐Locker method with differences arising from the use of either a saturation‐recovery or inversion‐recovery module prior to data acquisition with a full k‐space or banded k‐space acquisition scheme. The methods were implemented on a standard clinical scanner and the accuracy of the T1 results was evaluated against spectroscopic measurements. The accuracy of the T1 maps validated by phantom imaging measurements is around 1% for species which relax with T1 times that mimic gray/white matter (T1 ≤ 1000 ms). Additionally, the inherent multislice, multipoint capability of the methods is demonstrated. Finally, in vivo results of the human brain obtained using the faster method are presented. The fastest data acquisition was achieved with a saturation‐recovery, banded k‐space method where k‐space was divided into three segments; an overall acquisition time of around 5 min (for species with T1 ≤ 1 sec) was achieved for a T1 map which can, in principle, provide whole‐brain coverage with a matrix size of 256 × 256 at multiple time‐points. Magn Reson Med 46:131–140, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of regional pulmonary perfusion using ultrafast magnetic resonance imaging
Authors: Levin David L. , Chen Qun , Zhang Ming , Edelman Robert R. , Hatabu Hiroto 
Published: August 2002

AbstractAn ultrafast MR sequence was used to measure changes in signal intensity during the first pass of intravascular contrast through the pulmonary circulation. From this, mean transit time, relative blood volume, and relative blood flow were calculated. Data were collected in an isogravitational plane in six healthy subjects. A slight but significant gradient in transit time was present, with faster times at the lung apex. A significant decrease in blood volume, compared with the lung base, was also seen in the apex. Significant decreases in blood volume and blood flow, compared with central portions of the lung, were seen in the lung periphery. Six additional subjects were imaged along a gravitational plane. A significant gradient in transit time was seen, with faster transit in dependent regions of the lung. MRI is able to evaluate regional differences in pulmonary perfusion with high spatial and temporal resolution. Magn Reson Med 46:166–171, 2001. © 2001 Wiley‐Liss, Inc.
The effect of myelinating Schwann cells on axons
Authors: Martini Rudolf 
Published: August 2002

AbstractMyelinating Schwann cells control the number of neurofilaments and elevate the phosphorylation state of neurofilaments in the axon, eventually leading to the typical large axon caliber. Conversely, absence of myelin leads to lower amounts of neurofilaments, reduced phosphorylation levels, and smaller axon diameters. In addition, myelinating Schwann cells mediate the spacing of Na+ channel clusters during development of the node of Ranvier. When axons are associated with mutant Schwann cells in inherited neuropathies, their calibers are reduced and their neurofilaments are less phosphorylated and more closely spaced. Also, axonal transport is reduced and axons degenerate at the distal ends of long nerves. Myelin‐associated glycoprotein may mediate some aspects of Schwann cell–axon communication, but much remains to be learned about the molecular bases of Schwann cell–axon communication. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 456–466, 2001
Effects of cardiotrophin‐1 (CT‐1) in a mouse motor neuron disease
Authors: Mitsumoto Hiroshi , Klinkosz Bogdan , Pioro Erik P. , Tsuzaka Kazufumi , Ishiyama Takeo , O'Leary Rhona M. , Pennica Diane 
Published: August 2002

AbstractCardiotrophin‐1 (CT‐1) has potent survival‐promoting effects on motor neurons in vitro and in vivo and may be effective in treating motor neuron diseases (MND). We investigated the effects of CT‐1 treatment in wobbler mouse MND. Wobbler mice were randomly assigned to receive subcutaneously injected CT‐1 (1 mg/kg, n = 18, in two experiments) or vehicle (n = 18, in two experiments) daily, 6 times/week for 4 weeks after clinical diagnosis at age 3 to 4 weeks. Cardiotrophin‐1 treatment prevented deterioration in paw position and walking pattern abnormalities. Grip strength declined steadily in the vehicle group, whereas in the CT‐1 group it declined at week 1 but increased thereafter to exceed baseline strength by 5% (P = 0.0002) at week 4. Running speed was faster with CT‐1 (P = 0.007). Biceps muscle twitch tension, muscle weight, mean muscle fiber diameter, and intramuscular axonal sprouting were significantly greater with CT‐1 treatment than with vehicle treatment. Histometry revealed a trend that indicated CT‐1 modestly increased the number of immunoreactive motor neurons, as determined by both choline acetyltransferase and c‐Ret antibodies, and reduced the number of phosphorylated neurofilament immunoreactive perikarya (P = 0.05). The number of large myelinated motor axons significantly increased with treatment (206 versus 113, P = 0.01). We conclude that CT‐1 exerts myotrophic effects as well as neurotrophic effects in a mouse model of spontaneous MND, a finding that has potential therapeutic implications for human MND. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 769–777, 2001
A finite element algorithm for parameter identification of material models for fluid saturated porous media
Authors: Mahnken R. , Steinmann P. 
Published: August 2002

AbstractIn this contribution an algorithm for parameter identification of geometrically linear Terzaghi–Biot‐type fluid‐saturated porous media is proposed, in which non‐uniform distributions of the state variables such as stresses, strains and fluid pore pressure are taken into account. To this end a least‐squares functional consisting of experimental data and simulated data is minimized, whereby the latter are obtained with the finite element method. This strategy allows parameter identification based on in situ experiments. In order to improve the efficiency of the minimization process, a gradient‐based optimization algorithm is applied, and therefore the corresponding sensitivity analysis for the coupled two‐phase problem is described in a systematic manner. For illustrative purpose, the performance of the algorithm is demonstrated for a slope stability problem, in which a quadratic Drucker–Prager plasticity model for the solid and a linear Darcy law for the fluid are combined. Copyright © 2001 John Wiley & Sons, Ltd.
A TiO2 dielectric filled toroidal radio frequency cavity resonator for high‐field NMR
Authors: Butterworth Edward J. , Walsh Edward G. , Hugg James W. 
Published: August 2002

AbstractRF performance in high‐field MRI applications is improved by filling the resonator with material of relative dielectric constant approximating that of human soft tissue. We demonstrate this by filling a toroidal cavity resonator operating in TEM00 (cyclotron) mode with titanium dioxide (TiO2) in powdered rutile form, and acquiring phantom, human lower leg and human breast images of good quality at 4.1 T. Images made with this resonator had unusually high SNR, while the level of Rf power required to produce a 90° flip angle pulse was about a quartes as high for the filled resonator as for the same resonator before filling. Phantom images obtained with the filled resonator had an SNR of nearly 300 at a resolution of 256 × 256 voxels, nearly three times that of images of the same phantom obtained using a standard volume Rf coil in frequent use at this laboratory. Breast images made at 256 × 256 voxels resolution had an SNR of 174, also unusually high for a volume coil. High‐resolution (512 × 512 voxels) were also obtained, with SNR = 60. Preliminary phantom and in vivo human images are presented in this article. Acquiring the phantom and leg images required significantly less Rf power than did comparable imaging using a conventional coil. In addition, the field lines were focused as they penetrated into the sample, and this resulted in a more homogeneous B1‐field. We believe that these improvements occurred because the dielectric presence minimizes the large dielectric mismatch between air and sample. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

EM

electromagnetic

FOV

field‐of‐view, Rf, radio frequency

SNR

signal‐to‐noise ratio.
An approach to modeling performance evaluation on the ethernet with QoS parameters
Authors: Yang Shin‐Jer 
Published: August 2002

AbstractThis paper proposes an empirical approach to model the performance of Ethernet with QoS (Quality of Services) parameters. Hence, how to model the performance of Ethernet becomes a critical issue for the LAN implementation and operation. In the QoS approach, however, Ethernet network performance can be dynamically tuned by existing and enhanced operation parameters based on the current information status of the Ethernet LAN system. Consequently, Ethernet performance can be predicted and maintained through using the proposed methodology, and then to promote the system throughput. Copyright © 2001 John Wiley & Sons, Ltd.
Weighted proportional window control of TCP traffic
Authors: Aweya James , Ouellette Michel , Montuno Delfin Y. 
Published: August 2002

AbstractThis article describes a technique for weighted proportional window control of elastic traffic such as that generated by TCP. This is achieved through the modification of the receiver's advertised window of TCP connections sharing the bottleneck link while taking into account the price that each user of a connection has paid for the service and the total number of active connections sharing the bottleneck link. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of the effects of HGF, BDNF, CT‐1, CNTF, and the branchial arches on the growth of embryonic cranial motor neurons
Authors: Naeem Arifa , Abbas Leila , Guthrie Sarah 
Published: August 2002

AbstractIn the developing embryo, axon growth and guidance depend on cues that include diffusible molecules. We have shown previously that the branchial arches and hepatocyte growth factor (HGF) are growth‐promoting and chemoattractant for young embryonic cranial motor axons. HGF is produced in the branchial arches of the embryo, but a number of lines of evidence suggest that HGF is unlikely to be the only factor involved in the growth and guidance of these axons. Here we investigate whether other neurotrophic factors could be involved in the growth of young cranial motor neurons in explant cultures. We find that brain‐derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and cardiotrophin‐1 (CT‐1) all promote the outgrowth of embryonic cranial motor neurons, while glial cell line‐derived neurotrophic factor (GDNF) and neurotrophin‐3 (NT‐3) fail to affect outgrowth. We next examined whether HGF and the branchial arches had similar effects on motor neuron subpopulations at different axial levels. Our results show that HGF acts as a generalized rather than a specific neurotrophic factor and guidance cue for cranial motor neurons. Although the branchial arches also had general growth‐promoting effects on all motor neuron subpopulations, they chemoattracted different axial levels differentially, with motor neurons from the caudal hindbrain showing the most striking response. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 101–114, 2002
GABA exerts opposite influence on warm and cold sensitive neurons in medial preoptic area in rats
Authors: Jha Sushil K. , Islam Fakhrul , Mallick Birendra N. 
Published: August 2002

AbstractThe preoptic area regulates body temperature. GABA‐ergic terminals and receptors are present in this area. Local microinjection studies have shown that GABA, its agonist, and its antagonist in this area may modulate body temperature. However, there are warm and cold sensitive neurons, and they are known to be affected by local and peripheral temperatures. In order to understand the mechanism of action of GABA in temperature regulation at the cellular level it was necessary to study the effect of GABA on individual thermosensitive neurons in in vivo preparations. Hence, in this study the responses of preoptic area thermosensitive and insensitive neurons to microiontophoretic application of picrotoxin, a GABA‐A antagonist, were studied in anaesthetized rats. It was observed that a majority of both the thermosensitive and insensitive neurons were affected by microiontophoretic application of picrotoxin. Although almost an equal number of cold and warm sensitive neurons were affected, a majority of the cold sensitive neurons were excited, while a majority of the warm sensitive neurons were inhibited by picrotoxin. The results suggested that in normal conditions GABA acts through GABA‐A receptor in modulating the spontaneous activity of thermosensitive neurons in the preoptic area. Furthermore, the results of the present study taken together with other reports suggest that normally GABA exerts a direct inhibitory action on the cold sensitive neurons, while it acts on presynaptic heteroreceptors, possibly on norepinephrinergic afferent input terminals on the warm sensitive neurons, for mediating its action. © 2001 John Wiley & Sons, Inc. J Neurobiol 48: 291–300, 2001