bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slice offset frequency and shim adjustment for interactive steady‐state free‐precession (SSFP) imaging
Authors: Graves Martin J. , Wong Pauline , Priest Andrew N. , Black Richard T. , Lomas David J. 
Published: April 2009

AbstractPurposeTo devise a method allowing real‐time optimization of center frequency (CF) and shim for an interactive steady‐state free‐precession (SSFP) sequence by reformatting a previously acquired field map in the same orientation as the interactive acquisition.Materials and MethodsField maps were acquired in a rectangular parallel‐piped phantom and a normal volunteer. An SSFP sequence was modified to communicate the current slice offset and rotation to an external program that reformatted the field map into the same plane, calculated the CF and shim offsets, and passed them back to the sequence. CF offsets as a function of position for the phantom were compared with the scanner prescan‐determined offset.ResultsIn the phantom, the CF measurements agreed with the scanner‐determined offsets. Bland‐Altman analysis showed a bias of −14 Hz (field map – prescan) and limits of agreement of −28 to 0 Hz. In the volunteer there was a qualitative improvement in image quality when using the optimized center frequencies and shims.ConclusionThe proposed method demonstrates how CF and shim can be optimized for any interactively positioned slice, resulting in reduced off‐resonance artifacts. J. Magn. Reson. Imaging 2009;29:1230–1233. © 2009 Wiley‐Liss, Inc.
Regional atrophy of transcallosal prefrontal connections in cognitively normal APOE ϵ4 carriers
Authors: Filippini Nicola , Zarei Mojtaba , Beckmann Christian F. , Galluzzi Samantha , Borsci Genoveffa , Testa Cristina , Bonetti Matteo , Beltramello Alberto , Ghidoni Roberta , Benussi Luisa , Binetti Giuliano , Frisoni Giovanni B. 
Published: April 2009

AbstractPurposeTo investigate the possible effect of the APOE ϵ4 allele on age‐related regional volume loss within the corpus callosum (CC) in healthy ϵ4 allele carriers compared with noncarriers.Materials and MethodsA total of 211 subjects, ages 27 to 83 years, 51 ϵ4 carriers and 160 noncarriers underwent T1‐weighted MRI scan. All subjects had normal MRI scan and performed within normal range on a neuropsychological battery of tests. CC was segmented into seven functionally relevant regions using a previously published probabilistic map of the CC connectivity. We measured the volumes of the CC and its subregions. We used a regression model (with volumes as dependent and age as independent variables) and compared the slopes between carriers and noncarriers using an analysis of covariance model. We also carried out voxel‐based‐morphometry analysis to investigate the possible effect of the APOE ϵ4 gene on the gray matter.ResultsWe found that the volume of the CC and all subregions decreased with increasing age in both groups. The slope was steeper in the APOE ϵ4 carriers compared withthe noncarriers particularly in the prefrontal region (P = 0.02). No gray matter differences were observed between the two groups.ConclusionAPOE ϵ4 polymorphism is associated with accelerated age‐related volume loss in the prefrontal callosal tracts without gray matter loss. This result suggests the role of APOE ϵ4 in the brain aging by primarily affecting white matter structures particularly in the frontal lobe. J. Magn. Reson. Imaging 2009;29:1021–1026. © 2009 Wiley‐Liss, Inc.
Strain‐encoded cardiac MR during high‐dose dobutamine stress testing: Comparison to cine imaging and to myocardial tagging
Authors: Korosoglou Grigorios , Futterer Simon , Humpert Per M. , Riedle Nina , Lossnitzer Dirk , Hoerig Birgit , Steen Henning , Giannitsis Evangelos , Osman Nael F. , Katus Hugo A. 
Published: April 2009

AbstractPurposeTo investigate regional strain response during high‐dose dobutamine stress cardiac magnetic resonance imaging (DS‐CMR) using myocardial tagging and Strain‐Encoded MR (SENC).Materials and MethodsStress induced ischemia was assessed by wall motion analysis, by tagged CMR and by SENC in 65 patients with suspected or known CAD who underwent DS‐CMR in a clinical 1.5 Tesla scanner. Coronary angiography deemed as the standard reference for the presence or absence of CAD (≥50% diameter stenosis) in all patients.ResultsSENC and conventional tagging detected abnormal strain response in six and five additional patients, respectively, who were missed by cine images and proved to have CAD by angiography (P < 0.05 for SENC versus cine, P = 0.06 for tagging versus cine and p = NS for SENC versus tagging). On a per‐vessel level, wall motion analysis on cine images showed high specificity (95%) but moderate sensitivity (70%) for the detection of CAD. Tagging and SENC yielded significantly higher sensitivity of 81% and 89%, respectively (P < 0.05 for tagging and P < 0.01 for SENC versus wall motion analysis, and p = NS for SENC versus tagging), while specificity was equally high (96% and 94%, respectively, P = NS for all).ConclusionBoth the direct color‐coded visualization of strain on CMR images and the generation of additional visual markers within the myocardium with tagged CMR represent useful adjuncts for DS‐CMR, which may provide incremental value for the detection of CAD in humans. J. Magn. Reson. Imaging 2009;29:1053–1061. © 2009 Wiley‐Liss, Inc.
MRI‐based large deformation high dimensional mapping of the hippocampus in rats: Development and validation of the technique
Authors: Hogan R. Edward , Bouilleret Viviane , Liu Ying Rui , Wang Lei , Williams John P. , Jupp Bianca , Myers Damian , O'Brien Terence J. 
Published: April 2009

AbstractPurposeTo report the detection of structural and functional biological changes in living animals using small animal in vivo MRI that complements traditional ex vivo histological techniques. We report the development and validation of the application of large deformation high dimensional mapping (HDM‐LD) segmentation for the hippocampus in the rat.Materials and MethodsHigh resolution volumetric T2 weighted MRI images were acquired at 4.7 Tesla from six male in‐breed nonepileptic Wistar rats. Two HDM‐LD segmentations of the hippocampus (automated 1 and automated 2) were compared with the manual segmentations of two investigators who independently segmented the hippocampi (manual 1 and manual 2).ResultsThe mean overlap for the hippocampi between automated 1 and automated 2 for the right hippocampi was 94.4% (SD 1.0) and for the left hippocampi was 94.3% (SD 2.5), while the mean overlap between automated 1 and manual 1 for the right hippocampi was 91.4% (SD 1.3) and for the left hippocampi was 91.9% (SD 1.4). Mean values for absolute differences for comparisons of all the segmentations were the following: automated 1 versus automated 2, 3.2% (SD 1.0); manual 1 versus manual 2 6.82% (SD 5.22); automated 1 versus manual 1 13.0% (SD 1.8).ConclusionHDM‐LD can be applied to obtain accurate and reproducible three‐dimensional segmentations of the hippocampus from rat MR images. HDM‐LD will be a useful tool for investigations of hippocampal structural changes in vivo in rat models of human disease. J. Magn. Reson. Imaging 2009;29:1027–1034. © 2009 Wiley‐Liss, Inc.
Signal fluctuations induced by non‐T1‐related confounds in variable TR fMRI experiments
Authors: Hu Shuowen , Olulade Olumide , Tamer Gregory G. , Luh Wen‐Ming , Talavage Thomas M. 
Published: April 2009

AbstractPurposeTo assess and model signal fluctuations induced by non‐T1‐related confounds in variable repetition time (TR) functional magnetic resonance imaging (fMRI) and to develop a compensation procedure to correct for the non‐T1‐related artifacts.Materials and MethodsRadiofrequency disabled volume gradient sequences were effected at variable offsets between actual image acquisitions, enabling perturbation of the measurement system without perturbing longitudinal magnetization, allowing the study of non‐T1‐related confounds that may arise in variable TR experiments. Three imaging sessions utilizing a daily quality assurance (DQA) phantom were conducted to assess the signal fluctuations, which were then modeled as a second‐order system. A modified projection procedure was implemented to correct for signal fluctuations arising from non‐T1‐related confounds, and statistical analysis was performed to assess the significance of the artifacts with and without compensation.ResultsAssessment using phantom data reveals that the signal fluctuations induced by non‐T1‐related confounds was consistent in shape across the phantom and well‐modeled by a second‐order system. The phantom exhibited significant spurious detections (at P < 0.01) almost uniformly across the central slices of the phantom.ConclusionSecond‐order system modeling and compensation of non‐T1‐related confounds achieves significant reduction of spurious detection of fMRI activity in a phantom. J. Magn. Reson. Imaging 2009;29:1234–1239. © 2009 Wiley‐Liss, Inc.
A comprehensive analysis of changes in precipitation regime in Tuscany
Authors: Fatichi Simone , Caporali Enrica 
Published: April 2009

AbstractThe analysis of changes in precipitation is nowadays of great interest because rainfall space‐time distribution is considered one of the most important indexes in the natural climatic cycle. This study proposes an investigation of precipitation time series recorded in the region of Tuscany (Central Italy) in the period 1916–2003. Forty indexes are defined to evaluate changes in the precipitation patterns and trend detection is performed through statistical tests to assess the significance of temporal and spatial changes in the precipitation regime. The presented analysis does not show strong evidence of nonstationarity. A few indexes in a given number of stations of the analysed territory do show a slight trend, but the significance of those trends is lost once the multiple location testing issue is considered. The complexity of the climate in central Italy, i.e. the presence of numerous feedbacks might in fact distort or remove the consequences of global warming on the precipitation regime. Copyright © 2009 Royal Meteorological Society
Interdecadal variability of summer rainfall in Northwest China and its possible causes
Authors: Zhou Lian‐Tong , Huang Rong‐Hui 
Published: April 2009

AbstractThe present study investigates interdecadal variability of summer rainfall in Northwest China using station observations for the period 1951–2000 and the ERA‐40 reanalysis for the period 1958–2000. It is found that Northwest China summer rainfall experienced an obvious interdecadal increase around 1978. Analyses show that summer circulation, temperature and potential vorticity anomalies over Asia vary vastly before and after 1978. During the period 1978–2000, cyclonic and anti‐cyclonic circulation anomalies dominate over Northwest and North China, respectively. These are associated with the anomalous ascending motion over Northwest China, and their anomalous descending motion over North China. The temperature over Northwest China shows an obvious decrease at 300 hPa, but increase near the surface after 1978. This enhances convective instability, which contributes to the strengthening of ascent and the increase of summer rainfall in Northwest China during 1978–2000. Copyright © 2009 Royal Meteorological Society
Ultraviolet resonance Raman spectroscopy of locked single‐stranded oligo(dA) reveals conformational implications of the locked ribose in LNA
Authors: Konorov Stanislav O. , Georg Schulze H. , Addison Christopher J. , Haynes Charles A. , Blades Michael W. , Turner Robin F. B. 
Published: April 2009

AbstractWe report here the first UV resonance Raman spectroscopic (UVRRS) study on locked nucleic acid (LNA) oligomers. Locking a base in nucleic acid (NA) oligomers produces a conformational change in the glycosyl bond between backbone and base. We present evidence of this change in LNAs when compared to their natural analogs using UVRRS. Wavenumber downshifts and peak amplitude increases, especially of the ∼1481 cm−1 peak that is a spectral marker for part of the glycosyl bond, correlate with the fraction of locked bases when single‐stranded oligomers incorporating up to three locked bases were examined. By varying the position of the locked base within a fixed length sequence, we conclude that one, or at most two bases, on either side of the lock is affected. We further conclude from these data, and previously published reports, that the conformation of LNA is determined by imidazole–imidazole and pyrimidine–pyrimidine repulsion and imidazole–pyrimidine attraction in contrast to dispersion attraction‐dependent aggregation in the B conformation of DNA. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance Raman spectra and excited state structural dynamics of ethylene trithiocarbonate in the A‐ and B‐band absorptions
Authors: Wang Huigang , Liu Bo , Zhao Yanying , Zheng Xuming 
Published: April 2009

AbstractA‐ and B‐band resonance Raman spectra were acquired for ethylene trithiocarbonate in cyclohexane solution. The results indicate that the S3 state structural dynamics is mostly along vibrational motions of the CS stretch υ11, while the S4 state one has motions mainly via the SCS symmetric stretch υ18, CS stretch υ11, and the HCH rock + SCS antisymmetric stretch υ14 reaction coordinates. The very different excited state structural dynamics were briefly discussed in terms of vibronic couplings using local symmetry point group. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of enantioselective HPLC separation of structurally diverse compounds on chiral stationary phases with different teicoplanin coverage and distinct linkage chemistry
Authors: Honetschlägerová‐Vadinská Marie , Srkalová Simona , Bosáková Zuzana , Coufal Pavel , Tesarová Eva 
Published: April 2009

AbstractEnantioseparation performance of two teicoplanin‐based chiral stationary phases, Chirobiotic T and Chirobiotic T2, with different teicoplanin coverage and distinct linkage chemistry was compared. Three structurally diverse groups of analytes, amino alcohols (β‐blockers), chlorophenoxypropionic acids, and branched‐chain amino acids, in various mobile phase compositions/separation modes were examined. The amino alcohols showed better enantioresolution on Chirobiotic T2 in reverse‐phase, hydrophilic interaction chromatography, and polar‐ionic mode separation systems. The best results with these analytes were obtained in the polar‐ionic mobile phase. In contrast, the chlorophenoxypropionic acids and the branched‐chain amino acids yielded an improved enantioresolution on the chiral stationary phase with lower amount of teicoplanin in the hydrophilic interaction chromatography system. The comparison of separation of the chlorophenoxypropionic acids enantiomers in the reverse‐phase and hydrophilic interaction chromatography environments showed completely opposite results. While better enantioresolution of chlorophenoxypropionic acids was achieved on Chirobiotic T2 in mobile phases with low methanol content, high methanol concentration was needed to reach baseline enantioseparation on Chirobiotic T.
A genome‐inspired DNA ligand for the affinity capture of insulin and insulin‐like growth factor‐2
Authors: Xiao Junfeng , Carter Jennifer A. , Frederick Kimberley A. , McGown Linda B. 
Published: April 2009

AbstractThe insulin‐linked polymorphic region (ILPR) of the human insulin gene contains tandem repeats of similar G‐rich sequences, some of which form intramolecular G‐quadruplex structures in vitro. Previous work showed affinity binding of insulin to an intramolecular G‐quadruplex formed by ILPR variant a. Here, we report on interactions of insulin and the highly homologous insulin‐like growth factor‐2 (IGF‐2) with ILPR variants a, h, and i. Circular dichroism indicated intramolecular G‐quadruplex formation for variants a and h. Affinity MALDI MS and surface plasmon resonance were used to compare protein capture and binding strengths. Insulin and IGF‐2 exhibited high binding affinity for variants a and h but not i, indicating the involvement of intramolecular G‐quadruplexes. Interaction between insulin and variant a was unique in the appearance of two binding interactions with KD ∼︁ 10–13 M and KD ∼︁ 10–7 M, which was not observed for insulin with variant h (KD ∼︁ 10–8 M) or IGF‐2 with either variant (KDs ∼︁ 10–9 M). The results provide a basis for the design of DNA binding ligands for insulin and IGF‐2 and support a new approach to discovery of DNA affinity binding ligands based on genome‐inspired sequences rather than the traditional combinatorial selection route to aptamer discovery.
Zinc peroxide precursor for ZnO clusters
Authors: Dmytruk A. , Dmitruk I. , Kasuya A. 
Published: April 2009

AbstractZinc peroxide is suggested as a new precursor for formation of zinc oxide clusters. (ZnO)n, n=1–100 clusters have been produced by laser ablation of bulk powder of zinc peroxide and studied by time‐of‐flight mass spectroscopy.
Mineral distribution in highly fluorotic and in normal teeth: A synchrotron microcomputer tomographic study
Authors: Neues F. , Klocke A. , Beckmann F. , Herzen J. , Loyola‐Rodriguez J.P. , Epple M. 
Published: April 2009

AbstractA healthy and a fluorotic human molar tooth were studied by high‐resolution synchrotron microcomputer tomography (SRμCT) and compared with respect to their structure and mineral distribution. The teeth were measured in their full size, i.e. without introducing segmentation or cutting artefacts. Enamel and dentin were clearly separated on the basis of their different X‐ray absorption coefficient. No significant differences in the degree of mineralization were found between the healthy and the fluorotic tooth, except for a slightly rougher enamel surface of the fluorotic tooth.
On impurities and the internal structure in precipitates occurring during the precipitation of nanocrystalline calcium phosphate
Authors: Zyman Z. , Epple M. , Rokhmistrov D. , Glushko V. 
Published: April 2009

AbstractNanocrystalline calcium phosphate was precipitated at 20 °C from calcium nitrate and ammonium phosphate solutions at a pH of 9–11. The nature of the mass loss steps in thermogravimetry of the product was revealed by in‐situ mass spectrometry of released gases upon heating. Major amounts of nitrate‐containing impurities like NH4NO3 and Ca(NO3)2 were present which could only be removed by multiple washing with water. These impurities were not crystalline, but they were clearly detectable in the infrared spectrum. In conclusion, the high specific surface area of freshly precipitated calcium phosphate may cause the adsorption of considerable amounts of foreign compounds (molecules and ions) in the percent mass range.
Protective effects of C60 fullerenes on staurosporine‐, cytosine arabinoside‐ and hydrogen peroxide‐induced cell death of normal but not of transformed T lymphocytes
Authors: Palyvoda K. , Samoylenko A. , Drobot L. , Matyshevska O. , Scharff P. 
Published: April 2009

AbstractC60 fullerenes are carbon nanospheres known to exert a protective activity in several models of apoptotic cell death. Both normal rat thymocytes and human T‐cell lymphoma Jurkat cells were treated with staurosporine, cytosine arabinoside and hydrogen peroxide as agents that trigger cell death. Activation of caspase‐3 as apoptosis marker was demonstrated in cells incubated for 4 h in the presence of these agents at concentrations causing 50 % cell viability reduction. Addition of C60 fullerenes (10‐5 M) protected normal T cells but not human T lymphoma cells from apoptosis induced either by staurosporine, cytosine arabinoside or hydrogen peroxide. These data demonstrate selectivity of fullerenes C60 biological effects in cultures of normal and transformed T cells.
Influence of grain size on mechanical and corrosion properties of magnesium alloy for medical implants
Authors: Kutniy K.V. , Papirov I.I. , Tikhonovsky M.A. , Pikalov A.I. , Sivtzov S.V. , Pirozhenko L.A. , Shokurov V.S. , Shkuropatenko V.A. 
Published: April 2009

AbstractThe microstructure, mechanical property and corrosion behavior of magnesium alloy WE43 (MgYNdZr alloy) in the environment simulating biological fluid were investigated. Samples of ultra‐fine‐grained magnesium alloy with high mechanical properties were obtained by methods of severe plastic deformation. Programmed plastic deformation was realized by two methods: extrusion alternating with upsetting at gradually lowering the temperature and equal‐channel angular pressing.
Electrostatic control of occupancy and valence selectivity in a charged nanometer‐sized cylindrical pore
Authors: Spohr E. , Sovyak E. , Trokhymchuk A. , Busath D.D. 
Published: April 2009

AbstractSimple analytical calculations of the electrostatic energy for systems composed of positive charges confined to the axis of a negatively charged cylindrical pore are used to explore the role of electrostatic forces in the problems of ion permeation, ion occupancy and valence selectivity in biological ion channels. Considering the effect of finite length of the charged pore as an alternative to fixed charged residue representations, we show that ion occupancy and ion configurations in the pore are governed by two parameters: (i) the magnitude of the uniform surface charge density of the pore and (ii) the pore (diameter‐to‐length) aspect ratio through the interplay between favorable interaction of the mobile ions with the pore interior and unfavorable interaction among the ions themselves. The pore with an overall surface charge of ‐2e (representing a potassium channel) is found to favor occupancy by three K+ ions over two K+ ions at low aspect ratio but not at high. The pore with surface charge ‐4e (representing a calcium channel) favors occupancy by two lateral Ca2+ ions and one central Na+ ion over two symmetrically positioned Ca2+ ions at a low aspect ratio, but this preference is reversed at a higher aspect ratio. These results allow us to speculate that Ca2+ block of sodium current in the calcium channel is due to lower electrostatic energy for the Na+ ‐ Ca2+ ‐ Na+ configuration than for the Na+ ‐ Na+ ‐ Na+ configuration, and that the yet lower energy of the Ca2+ ‐ Ca2+ configuration would facilitate Ca2+ relief of Ca2+ block.
Peculiarities of nickel‐aluminium ferrites nanopowder structure
Authors: Kopayev A.V. , Ostafiychuk B.K. , Vylka I.Y. , Zadnipryannyy D.L. 
Published: April 2009

AbstractThe ferrites powders of the compound NiAltFe2‐tO4 were produced up to technology of sol‐gel autocombustion. In accordance with x‐ray defractional analysis data the powder particles’ size is 18–33 nanometers. The magnetic and electronic ferrites structure was researched with the help of XANES and Mössbauer spectroscopy methods. The iron ions valency is equal + 3. Magnetic penetrability depends upon the content of nickel ions in the tetrahedral lattice points. The calculation shows that while increasing the nickel concentration in the tetrahedral lattice points the constant of magnetoelastic anisotropy is growing.
Are multi‐resort ski conglomerates more efficient?
Authors: Falk Martin 
Published: April 2009

AbstractThis paper compares the efficiency of large ski resort conglomerates with independent ski resorts using data on four countries (Canada, France, United States, Switzerland). Using the stochastic frontier production approach, I find that ski resorts that are owned and managed by the Intrawest group are significantly more efficient than independent ski resorts. The efficiency gap is about nine percentage points on average. The remaining ski resort conglomerates (American Skiing, Vail Resorts Inc., and Compagnie des Alpes SA) do not operate more efficiently than independent ski resorts. Copyright © 2009 John Wiley & Sons, Ltd.