bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chiral 6,6′‐Bis(oxazolyl)‐1,1′‐biphenyls as Ligands for Copper(I)‐Catalyzed Asymmetric Cyclopropanation
Authors: Khanbabaee Karamali , Basceken Sinan , Flörke Ulrich 
Published: November 2006

AbstractA series of chiral bis(oxazoline)s with biphenyl backbones were synthesized from enantiomerically pure (S)‐ and (R)‐hexabenzyloxydiphenic acid (1) and their utility in copper(I)‐catalyzed asymmetric cyclopropanation was investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Total Synthesis of (±)‐Decursivine
Authors: Leduc Andrew B. , Kerr Michael A. 
Published: November 2006

AbstractThe first preparation of the antimalarial natural product decursivine is described. A Diels–Alder/Plieninger indolization protocol allows convenient preparation of the indole 15 which, in turn is a suitable substrate for a boron–enolate aldol reaction with piperonal (16). The resulting adduct 14 is transformed efficiently to the natural product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Numerical study of transitional separated–reattached flow over surface‐mounted obstacles using large‐eddy simulation
Authors: Abdalla Ibrahim E. , Cook Malcolm J. , Yang Zhiyin 
Published: November 2006

AbstractLarge‐eddy simulation (LES) of transitional separating–reattaching flow on a square surface mounted obstacle has been performed. The Reynolds number based on the uniform inlet velocity and the obstacle height is 4.5 × 103. A dynamic subgrid‐scale model is employed in this work. The mean LES results compare favourably with the available experimental and direct numerical simulation (DNS) data. Extensive analysis of the time series signals of the velocity and pressure fields at different locations including positions close to solid surfaces, at the centre and edge of the separated–reattached boundary layer using the windowed Fourier transform (WFT) and the wavelet transform was performed. The spectra analysis revealed the nature of the amplified frequencies at all the important locations of the flow field. Excited modes that could be due to the movement (shedding) of large‐scale structures and pairing of such types of structures are identified. A clear frequency peak was captured just upstream of the separation line. The value of the frequency peak and the low percentage of the back flow velocity compared to the freestream velocity in the current case strongly support the idea that this amplified frequency is most likely due to the Kelvin–Helmholtz (K–H) instability mechanism of the shear layer forming in the boundary of the small upstream separated region rather than being attributed to the flapping of the shear layer. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of Thermal Treatment on RuSe Cathode Materials for Direct Methanol Fuel Cells
Authors: Cheng H. , Yuan W. , Scott K. 
Published: November 2006

AbstractThe effect of thermal treatment on the activity of the carbon‐supported ruthenium and selenium cathode catalysts for the oxygen reduction reaction is evaluated in both half‐cells and in fuel cells, using voltammetric and steady‐state polarisation techniques. The catalysts treated at 300 and 400 °C give a better performance compared to that of the as prepared samples. The catalysts are characterised by scanning electron microscopy, energy‐dispersive X‐ray spectrometry, and X‐ray diffractometry in terms of the crystalline state, morphology, and composition of the materials. The formation of porous RuSe binary interfaces and the transformation from the amorphous to crystalline state are directly linked to the heat treatment temperatures, which in turn, affect the activity and methanol tolerance of the catalysts. The RuSe/C is compared to Pt/C cathode materials.
Characteristics of La0.85Sr0.15MnO3–δ Powders Synthesized by a Glycine‐Nitrate Process
Authors: Peng R. , Fan X. , Jiang Z. , Xia C. 
Published: November 2006

AbstractThe amount of glycine added, i.e., the glycine/oxide molar ratio, k, is optimized for synthesizing La0.85Sr0.15MnO3‐δ (LSM) powders by a glycine‐nitrate process. The specific surface area of the resultant LSM powders increases with this ratio, which indicates the deviation of the required glycine from the stoichiometric reaction. The powder is further characterized as a precursor for LSM‐SDC (samarium‐doped ceria) composite electrodes for solid oxide fuel cells. The electronic conductivity of the LSM‐SDC composite increases with increases in the glycine/oxide ratio. In addition, the ratio has an effect on the interfacial polarization resistance of the LSM‐SDC electrodes, as determined with symmetric cells using AC impedance spectroscopy. The lowest resistance is achieved using a LSM powder prepared with 20% more glycine than the stoichiometric requirement (k = 1.2). The activation energies for electrochemical oxygen reduction are about 1.3 eV, when the ratio is below 1.2, and about 1.0 eV, when it exceeds 1.2. The activation energy suggests that oxygen ion transfer is the rate determining process for the LSM‐SDC electrode when k ≥ 1.2, whereas both mass transfer and charge transfer are the rate limiting steps when k < 1.2.
Regulation of emotional responses elicited by threat‐related stimuli
Authors: Eippert Falk , Veit Ralf , Weiskopf Nikolaus , Erb Michael , Birbaumer Niels , Anders Silke 
Published: November 2006

AbstractThe capacity to voluntarily regulate emotions is critical for mental health, especially when coping with aversive events. Several neuroimaging studies of emotion regulation found the amygdala to be a target for downregulation and prefrontal regions to be associated with downregulation. To characterize the role of prefrontal regions in bidirectional emotion regulation and to investigate regulatory influences on amygdala activity and peripheral physiological measures, a functional magnetic resonance imaging (fMRI) study with simultaneous recording of self‐report, startle eyeblink, and skin conductance responses was carried out. Subjects viewed threat‐related pictures and were asked to up‐ and downregulate their emotional responses using reappraisal strategies. While startle eyeblink responses (in successful regulators) and skin conductance responses were amplified during upregulation, but showed no consistent effect during downregulation, amygdala activity was increased and decreased according to the regulation instructions. Trial‐by‐trial ratings of regulation success correlated positively with activity in amygdala during upregulation and orbitofrontal cortex during downregulation. Downregulation was characterized by left‐hemispheric activation peaks in anterior cingulate cortex, dorsolateral prefrontal cortex, and orbitofrontal cortex and upregulation was characterized by a pattern of prefrontal activation not restricted to the left hemisphere. Further analyses showed significant overlap of prefrontal activation across both regulation conditions, possibly reflecting cognitive processes underlying both up‐ and downregulation, but also showed distinct activations in each condition. The present study demonstrates that amygdala responses to threat‐related stimuli can be controlled through the use of cognitive strategies depending on recruitment of prefrontal areas, thereby changing the subject's affective state. Hum Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
fMRI study of effort and information processing in a working memory task
Authors: Jansma J.M. , Ramsey N.F. , de Zwart J.A. , van Gelderen P. , Duyn J.H. 
Published: November 2006

AbstractIt is unclear how effort translates into brain function. In this study we endeavored to identify the activity in a working memory task that is related to the allocation of mental resources. Such activity, if present, would be a likely candidate to explain how effort works in terms of brain function. Eleven healthy participants performed a Sternberg task with a memory‐set of one, three, or five consonants in an fMRI study. Probe stimuli were either one consonant or one digit. We expected digits to be processed automatically and consonants to require working memory. Because the probe type was unpredictable and subjects had to respond as fast as possible, we expected subjects to allocate mental resources on the basis of the memory‐set size, not the probe type. Accordingly, we anticipated that activity in regions involved in effort would be a function of the size of the memory‐set, but independent of the type of probe. We found that the reaction‐time for digits increased in line with our expectation of automatic processing and the reaction time for letters increased in line with our expectation of controlled processing. fMRI revealed that activity in the right ventral‐prefrontal cortex changed as a function of effort. The ventral anterior cingulate cortex and hypothalamus showed reduced activity as a function of effort. Activity in regions regarded as pivotal for working memory (among others, the left dorsolateral prefrontal cortex, anterior cingulate cortex) appeared to be predominantly related to information processing and not involved in effort. Hum Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
The interaction between orthographic and phonological information in children: An fMRI study
Authors: Bitan Tali , Burman Douglas D. , Chou Tai‐Li , Lu Dong , Cone Nadia E. , Cao Fan , Bigio Jordan D. , Booth James R. 
Published: November 2006

AbstractWe examined the neural representations of orthographic and phonological processing in children, while manipulating the consistency between orthographic and phonological information. Participants, aged 9–15, were scanned while performing rhyming and spelling judgments on pairs of visually presented words. The orthographic and phonological similarity between words in the pair was independently manipulated, resulting in four conditions. In the nonconflicting conditions, both orthography and phonology of the words were either (1) similar (lime‐dime) or (2) different (staff‐gain); in conflicting conditions, words had (3) similar phonology and different orthography (jazz‐has) or (4) different phonology and similar orthography (pint‐mint). The comparison between tasks resulted in greater activation for the rhyming task in bilateral inferior frontal gyri (BA 45/47), and greater activation for the spelling task in bilateral inferior/superior parietal lobules (BA 40/7), suggesting greater involvement of phonological and semantic processing in the rhyming task, and nonlinguistic spatial processing in the spelling task. Conflicting conditions were more difficult in both tasks and resulted in greater activation in the above regions. The results suggest that when children encounter inconsistency between orthographic and phonological information they show greater engagement of both orthographic and phonological processing. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Altered functional connectivity in early Alzheimer's disease: A resting‐state fMRI study
Authors: Wang Kun , Liang Meng , Wang Liang , Tian Lixia , Zhang Xinqing , Li Kuncheng , Jiang Tianzi 
Published: November 2006

AbstractPrevious studies have led to the proposal that patients with Alzheimer's disease (AD) may have disturbed functional connectivity between different brain regions. Furthermore, recent resting‐state functional magnetic resonance imaging (fMRI) studies have also shown that low‐frequency (<0.08 Hz) fluctuations (LFF) of the blood oxygenation level‐dependent signals were abnormal in several brain areas of AD patients. However, few studies have investigated disturbed LFF connectivity in AD patients. By using resting‐state fMRI, this study sought to investigate the abnormal functional connectivities throughout the entire brain of early AD patients, and analyze the global distribution of these abnormalities. For this purpose, the authors divided the whole brain into 116 regions and identified abnormal connectivities by comparing the correlation coefficients of each pair. Compared with healthy controls, AD patients had decreased positive correlations between the prefrontal and parietal lobes, but increased positive correlations within the prefrontal lobe, parietal lobe, and occipital lobe. The AD patients also had decreased negative correlations (closer to zero) between two intrinsically anti‐correlated networks that had previously been found in the resting brain. By using resting‐state fMRI, our results supported previous studies that have reported an anterior–posterior disconnection phenomenon and increased within‐lobe functional connectivity in AD patients. In addition, the results also suggest that AD may disturb the correlation/anti‐correlation effect in the two intrinsically anti‐correlated networks. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Real‐time fMRI using brain‐state classification
Authors: LaConte Stephen M. , Peltier Scott J. , Hu Xiaoping P. 
Published: November 2006

AbstractWe have implemented a real‐time functional magnetic resonance imaging system based on multivariate classification. This approach is distinctly different from spatially localized real‐time implementations, since it does not require prior assumptions about functional localization and individual performance strategies, and has the ability to provide feedback based on intuitive translations of brain state rather than localized fluctuations. Thus this approach provides the capability for a new class of experimental designs in which real‐time feedback control of the stimulus is possible—rather than using a fixed paradigm, experiments can adaptively evolve as subjects receive brain‐state feedback. In this report, we describe our implementation and characterize its performance capabilities. We observed ∼80% classification accuracy using whole brain, block‐design, motor data. Within both left and right motor task conditions, important differences exist between the initial transient period produced by task switching (changing between rapid left or right index finger button presses) and the subsequent stable period during sustained activity. Further analysis revealed that very high accuracy is achievable during stable task periods, and that the responsiveness of the classifier to changes in task condition can be much faster than signal time‐to‐peak rates. Finally, we demonstrate the versatility of this implementation with respect to behavioral task, suggesting that our results are applicable across a spectrum of cognitive domains. Beyond basic research, this technology can complement electroencephalography‐based brain computer interface research, and has potential applications in the areas of biofeedback rehabilitation, lie detection, learning studies, virtual reality‐based training, and enhanced conscious awareness. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Bayesian comparison of spatially regularised general linear models
Authors: Penny Will , Flandin Guillaume , Trujillo‐Barreto Nelson 
Published: November 2006

AbstractIn previous work (Penny et al., [2005]: Neuroimage 24:350–362) we have developed a spatially regularised General Linear Model for the analysis of functional magnetic resonance imaging data that allows for the characterisation of regionally specific effects using Posterior Probability Maps (PPMs). In this paper we show how it also provides an approximation to the model evidence. This is important as it is the basis of Bayesian model comparison and provides a unified framework for Bayesian Analysis of Variance, Cluster of Interest analyses and the principled selection of signal and noise models. We also provide extensions that implement spatial and anatomical regularisation of noise process parameters. Hum Brain Mapp 2007. © 2006 Wiley‐Liss, Inc.
High‐resolution fMRI investigation of the medial temporal lobe
Authors: Kirwan C. Brock , Jones Craig K. , Miller Michael I. , Stark Craig E.L. 
Published: November 2006

AbstractThe medial temporal lobe (MTL) is critical for declarative memory formation. Several theories of MTL function propose functional distinctions between the different structures of the MTL, namely the hippocampus and the surrounding cortical areas. Furthermore, computational models and electrophysiological studies in animals suggest distinctions between the subregions of the hippocampus itself. Standard fMRI resolution is not sufficiently fine to resolve activity on the scale of hippocampal subregions. Several approaches to scanning the MTL at high resolutions have been made, however there are limitations to these approaches, namely difficulty in conducting group‐level analyses. We demonstrate here techniques for scanning the MTL at high resolution and analyzing the high‐resolution fMRI data at the group level. To address the issue of cross‐participant alignment, we employ the ROI‐LDDMM alignment technique, which is demonstrated to result in smaller alignment errors when compared with several other common normalization techniques. Finally, we demonstrate that the pattern of activation obtained in the high‐resolution functional data is similar to that obtained at lower resolution, although the spatial extent is smaller and the percent signal change is greater. This difference in the pattern of activation may be due to less partial volume sampling in the high‐resolution data, resulting in more accentuated regions of activation. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
A picture says more than a thousand words: Structural insights into hepatitis C virus translation initiation
Authors: Bellecave Pantxika , Moradpour Darius 
Published: November 2006

Abstract

Protein synthesis in mammalian cells requires initiation factor eIF3, a ˜750-kilodalton complex that controls assembly of 40S ribosomal subunits on messenger RNAs (mRNAs) bearing either a 5′-cap or an internal ribosome entry site (IRES). Cryoelectron microscopy reconstructions show that eIF3, a five-lobed particle, interacts with the hepatitis C virus (HCV) IRES RNA and the 5′-cap binding complex eIF4F via the same domain. Detailed modeling of eIF3 and eIF4F onto the 40S ribosomal subunit reveals that eIF3 uses eIF4F or the HCV IRES in structurally similar ways to position the mRNA strand near the exit site of 40S, promoting initiation complex assembly.
H. pylori and platelet counts
Authors: Arnold Hays L. , Harrison Stephen A. 
Published: November 2006

Abstract

Helicobacter pylori (HP) eradication therapy is a useful treatment for idiopathic thrombocytopenic purpura (ITP). Some investigators have also reported the effects of proton pump inhibitor (PPI) monotherapy on ITP. We performed a randomized study of HP eradication therapy and PPI monotherapy on ITP. Four of nine patients achieved complete remission (CR), two of nine achieved partial remission (PR) in HP eradication therapy, three of eight achieved CR, and two of eight achieved PR in PPI monotherapy. No significant differences were observed in the CR + PR of these patients between HP eradication therapy and PPI monotherapy. As for cost comparisons, HP eradication therapy is cheaper than PPI monotherapy, but it is less effective.
Apoptotic signaling in methylglyoxal‐treated human osteoblasts involves oxidative stress, c‐Jun N‐terminal kinase, caspase‐3, and p21‐activated kinase 2
Authors: Chan Wen‐Hsiung , Wu Hsin‐Jung , Shiao Nion‐Heng 
Published: November 2006

AbstractMethylglyoxal (MG) is a reactive dicarbonyl compound endogenously produced mainly from glycolytic intermediates. MG is cytotoxic through induction of cell death, and elevated MG levels in diabetes patients are believed to contribute to diabetic complications. In this report, we show for the first time that MG treatment triggers apoptosis in human osteoblasts. We further show that MG‐induced apoptosis of osteoblasts involves specific apoptotic biochemical changes, including oxidative stress, c‐Jun N‐terminal kinase (JNK) activation, mitochondrial membrane potential changes, cytochrome C release, increased Bax/Bcl‐2 protein ratios, and activation of caspases (caspase‐9, caspase‐3) and p21‐activated protein kinase 2 (PAK2). Treatment of osteoblasts with SP600125, a JNK‐specific inhibitor, led to a reduction in MG‐induced apoptosis and decreased activation of caspase‐3 and PAK2, indicating that JNK activity is upstream of these events. Experiments using anti‐sense oligonucleotides against PAK2 further showed that PAK2 activation is required for MG‐induced apoptosis in osteoblasts. Interestingly, we also found that MG treatment triggered nuclear translocation of NF‐κB, although the precise regulatory role of NF‐κB activation in MG‐induced apoptosis remains unclear. Lastly, we examined the effect of MG on osteoblasts in vivo, and found that exposure of rats to dietary water containing 100–200 µM MG caused bone mineral density (BMD) loss. Collectively, these results reveal for the first time that MG treatment triggers apoptosis in osteoblasts via specific apoptotic signaling, and causes BMD loss in vivo. J. Cell. Biochem. 100: 1056–1069, 2007. © 2006 Wiley‐Liss, Inc.
A possible role of autogenous IFN‐β for cytokine productions in human fibroblasts
Authors: Sano Emiko , Ohashi Kensaku , Sato Yuichiro , Kashiwagi Masamitsu , Joguchi Atsuhiro , Naruse Norio 
Published: November 2006

AbstractIt has been already known that human diploid fibroblasts are able to produce not only high levels of IFN‐β but also various kinds of cytokines by poly rI: poly rC, and some inflammatory cytokines are induced by IFN‐β gene activation. We also obtained similar results. However, in our system, cytokine productions were extremely enhanced by treating the cells with a low dose of type 1 IFN and the priming effects on cytokine productions were blocked by cycloheximide similar to those on IFN‐β productions. Most of cytokines were produced later than IFN‐β and synthesis patterns of their mRNA showed the same phenomena. We made clear that cytokine productions by poly rI: poly rC are mediated by secreted IFN‐β at a protein level using a monoclonal antibody against human IFN‐β. Further, it was shown that intra‐cellular IFN‐β which is not secreted might also participate in cytokine productions. Meanwhile, IL‐1β induced various kinds of cytokines in human fibroblasts and production time courses of these cytokines were similar to those of poly rI: poly rC induced cytokines. Although secreted IFN‐β was not detected in IL‐1β stimulated culture, expression of IFN‐β mRNA was augmented. These results showed that priming effects of type 1 IFN on cytokine productions by poly rI: poly rC might not be the direct action, but successive IFN‐β production might be essential in the production processes of other cytokines. Further, it was suggested that inducible IFN‐β might also take part in IL‐1β‐induced cytokine productions. J. Cell. Biochem. 100: 1459–1476, 2007. © 2006 Wiley‐Liss, Inc.