julilili42/papers huggingface dataset:
OC175: Three‐dimensional echocardiographic cine loop evaluation of ventricular septal defects in the fetus
2004-08-01

The purpose of this study was to investigate the feasibility of a new imaging technique using three-dimensional multiplanar sonography to reconstruct and display the site and spatial orientation of ventricular septal defects as part of a complex cardiac anomaly in fetuses and to determine whether any advantage is offered by this three-dimensional evaluation over conventional fetal echocardiography. After 2-D fetal echocardiographic examination 3-D multiplanar datasets of the beating fetal heart using either Doppler-gating or spatio-temporal image correlation (STIC) were collected prospectively in 22 fetuses with various types of ventricular septal defects involving any part of the different portions of the interventricular septum. The ages of the fetuses ranged from 19 to 35 weeks' gestation. Basic echocardiographic key views of the venoatrial, atrioventricular and ventriculoarterial connections were derived from the multiplanar data sets and selected for 2-D and 3-D analysis. Comparisons were made with conventional 2-D real-time echocardiographic imaging and the diagnostic image quality of interventricular and interatrial details was evaluated. The underlying cardiac malformation was well or satisfactorily visualized in all 22 fetuses using 2-D imaging. 3-D data sets enabled diagnostically acceptable visualization of all affected cardiac structures in 7 of 22 fetuses. A multiplanar 3-D reconstruction of the site and spatial orientation of septal defects involving any part of the different portions of the interventricular septum could be obtained in 9 patients. Multiplanar imaging of ventricular septal defects is feasible in a wide range of fetal cardiac lesions, and may provide additional information of clinical value when compared with 2-D imaging. However 2-D imaging remained the principal diagnostic modality in all cases with additional structural detail obtained by 3-D imaging in only some fetuses.
Basic level categorization and shape processing -- an fMRI study
2004-08-01

How is basic level categorization achieved in the human brain? Behavioral studies showed that categorization performance depends systematically on the amount of morph transformation (e.g. Graf, 2002). These results may be due to time-consuming compensation processes (deformable template matching). If deforming (i.e. spatial) compensation processes are involved, then categorization might not only comprise the ventral visual pathway, as generally assumed, but also the dorsal stream. Objects from 25 common basic level categories were generated by morphing between two category members (using 3ds max). In the categorization task, subjects had to decide as fast as possible whether two sequentially presented objects belonged to the same category. The morph distance between category members was varied (event-related design). In a second task, the same observers perceived intact morphing sequences, scrambled sequences, and static presentations of different morphs (block design). In the categorization task, response latencies increased with increasing morph distance between exemplars. Correspondingly, the BOLD signal increased with increasing morph distance in the lateral occipital complex, the superior parietal and the frontal cortices. Control analyses showed that this pattern of activation cannot be reduced to task difficulty, or increasing shape dissimilarity. In the second task we found parietal activation for the contrast between intact vs. scrambled morphing sequences which was close to the dorsal activation in the categorization task, but not identical. The results suggest that basic level categorization relies on a network of ventral, dorsal and frontal areas. The activation within this network depends systematically on the amount of shape transformation. The dorsal activation seems related to compensation processes in parietal cortex, i.e. spatial (deforming) transformation processes. These findings are in accordance with an alignment approach of categorization.
P02.07: Fetal cardiac intervention—is the chick embryo a suitable animal model?
2004-08-01

Babies with hypoplastic left (HLHS) or right heart syndrome and associated hypoplasia of the great arteries continue to be a challenge in terms of survival. Early knowledge of these conditions encourages some researchers to explore new minimal invasive therapeutic options with a view to in utero cardiac palliation. The upcoming expansion of fetal cardiac interventions to ameliorate critically progressive fetal cardiac lesions intensifies the need to address issues about the adequacy of technology assessment in a suitable animal model. 13 intracardiac interventions were performed in chick embryos 3 days prior to hatching using transamniotic local anesthesia and fentanyl for fetal analgesia. After cutting a window in the shell above the previously candled embryo transamniotic intraventricular access was obtained using 22 gauge needles under ultrasound guidance. All hearts were evaluated by histological preparation after hatching. All procedures were technically successful, however four of the study objects did not survive the first 24 hours after the procedure. Neither the myocardial or endocardial layers nor the outflow tract morphology of the surviving animals showed any signs of structural damage. Transamniotic intracardiac access is technically feasible and allowed survival to term in 9 of the 13 embryos studied.
Fully renormalized quasi-particle random phase approximation, spurious states and ground state correlations
2004-08-03

An approach, called fully renormalized QRPA (FR-QRPA), which takes into account the Pauli principle for the ground state correlations (GSC) and fulfills the Ikeda sum rule has recently been developed. Here a new rotational invariant model of the 1+ states is formulated within the FR-QRPA and deformed nuclei 150Nd, 154Sm and 168Er are studied. Two different Hamiltonians are used to describe the low-lying excited states (the famous scissors mode). One Hamiltonian is constructed to be rotational invariant and the spurious rotational state is separated by moving its energy to zero. The second Hamiltonian mixes the spurious rotational state with different vibrational states having the same quantum numbers. The GSC measured by the number of quasiparticles in the ground state are studied for the Hamiltonians within the QRPA, R-QRPA and FR-QRPA approaches. The present investigation demonstrates an advantage of the FR-QRPA over the other approaches. Within the rotational invariant FR-QRPA the GSC are stronger than within the R-QRPA by about 20%. The spurious rotational state in the rotational invariant case contributes within the FR-QRPA more than 50% to the total number of quasiparticles in the ground state of the nuclei in question.
Defined Inactive FecA Derivatives Mutated in Functional Domains of the Outer Membrane Transport and Signaling Protein of Escherichia coli K-12
2004-08-03

ABSTRACT The FecA outer membrane protein of Escherichia coli functions as a transporter of ferric citrate and as a signal receiver and signal transmitter for transcription initiation of the fec transport genes. Three FecA regions for which functional roles have been predicted from the crystal structures were mutagenized: (i) loops 7 and 8, which move upon binding of ferric citrate and close the entrance to the ferric citrate binding site; (ii) the dinuclear ferric citrate binding site; and (iii) the interface between the globular domain and the β-barrel. Deletion of loops 7 and 8 abolished FecA transport and induction activities. Deletion of loops 3 and 11 also inactivated FecA, whereas deletion of loops 9 and 10 largely retained FecA activities. The replacement of arginine residue R365 or R380 and glutamine Q570, which are predicted to serve as binding sites for the negatively charged dinuclear ferric citrate, with alanine resulted in inactive FecA, whereas the binding site mutant R438A retained approximately 50% of the FecA induction and transport activities. Residues R150, E541, and E587, conserved among energy-coupled outer membrane transporters, are predicted to form salt bridges between the globular domain and the β-barrel and to contribute to the fixation of the globular domain inside the β-barrel. Mutations E541A and E541R affected FecA induction and transport activity slightly, whereas mutations E587A and E587R more strongly reduced FecA activity. The double mutations R150A E541R and R150A E587R nearly abolished FecA activity. Apparently, the salt bridges are less important than the individual functions these residues seem to have for FecA activity. Comparison of the properties of the FecA, FhuA, FepA, and BtuB transporters indicates that although they have very similar crystal structures, the details of their functional mechanisms differ.
Brain activity underlying emotional valence and arousal: A response‐related fMRI study
2004-08-05

Abstract Emotional behavior is organized along two psychophysiologic dimensions: (1) valence, varying from negative to positive, and (2) arousal, varying from low to high. Behavioral responses along these dimensions are assumed to be mediated by different brain circuits. We recorded startle reflex modulation and skin conductance responses in healthy volunteers during functional magnetic resonance imaging (fMRI) while they viewed a set of emotional pictures and took verbal ratings of the emotional valence and arousal of each picture after scanning. Response‐related multiple correlation analysis revealed differential brain activity in five brain regions. Startle reflex changes, associated with the valence of a stimulus, correlated with activity in the amygdala, while verbal reports of negative emotional valence varied with insular activity. Peripheral physiologic and verbal responses along the arousal dimension varied with thalamic and frontomedial activity. Peripheral physiologic responses along both dimensions correlated with activity in somatosensory association areas in the anterior parietal cortex. In the valence dimension, activity in the left anterior parietal cortex was associated with highly correlating peripheral physiologic and verbal responses, suggesting that verbal reports of emotional valence might depend partly on brain circuits representing peripheral physiologic changes. Our data provide direct evidence for a functional segregation of brain structures underlying peripheral physiologic responses and verbal ratings along the emotional dimensions of valence and arousal. Hum. Brain Mapp. 23:200–209, 2004. © 2004 Wiley‐Liss, Inc.
Cloning, Heterologous Expression, and Characterization of Three Aquaglyceroporins from Trypanosoma brucei
2004-08-05

Trypanosoma brucei, causative for African sleeping sickness, relies exclusively on glycolysis for ATP production. Under anaerobic conditions, glucose is converted to equimolar amounts of glycerol and pyruvate, which are both secreted from the parasite. As we have shown previously, glycerol transport in T. brucei occurs via specific membrane proteins (Wille, U., Schade, B., and Duszenko, M. (1998) Eur. J. Biochem. 256, 245-250). Here, we describe cloning and biochemical characterization of the three trypanosomal aquaglyceroporins (AQP; TbAQP1-3), which show a 40-45% identity to mammalian AQP3 and -9. AQPs belong to the major intrinsic protein family and represent channels for small non-ionic molecules. Both TbAQP1 and TbAQP3 contain two highly conserved NPA motifs within the pore-forming region, whereas TbAQP2 contains NSA and NPS motifs instead, which are only occasionally found in AQPs. For functional characterization, all three proteins were heterologously expressed in yeast and Xenopus oocytes. In the yeast fps1Delta mutant, TbAQPs suppressed hypoosmosensitivity and rendered cells to a hyper-osmosensitive phenotype, as expected for unregulated glycerol channels. Under iso- and hyperosmotic conditions, these cells constitutively released glycerol, consistent with a glycerol efflux function of TbAQP proteins. TbAQP expression in Xenopus oocytes increased permeability for water, glycerol and, interestingly, dihydroxyacetone. Except for urea, TbAQPs were virtually impermeable for other polyols; only TbAQP3 transported erythritol and ribitol. Thus, TbAQPs represent mainly water/glycerol/dihydroxyacetone channels involved in osmoregulation and glycerol metabolism in T. brucei. This function and especially the so far not investigated transport of dihydroxyacetone may be pivotal for the survival of the parasite survival under non-aerobic or osmotic stress conditions.
QUASIPARTICLE UNIVERSES IN BOSE–EINSTEIN CONDENSATES
2004-08-05

Recent developments in simulating fundamental quantum field theoretical effects in the kinematical context of analogue gravity are reviewed. Specifically, it is argued that a curved spacetime generalization of the Unruh–Davies effect — the Gibbons–Hawking effect in the de Sitter spacetime of inflationary cosmological models — can be implemented and verified in an ultracold gas of bosonic atoms.
K + channel interactions detected by a genetic system optimized for systematic studies of membrane protein interactions
2004-08-06

Organization of proteins into complexes is crucial for many cellular functions. However, most proteomic approaches primarily detect protein interactions for soluble proteins but are less suitable for membrane-associated complexes. Here we describe a mating-based split ubiquitin system (mbSUS) for systematic identification of interactions between membrane proteins as well as between membrane and soluble proteins. mbSUS allows in vivo cloning of PCR products into a vector set, detection of interactions via mating, regulated expression of baits, and improved selection of interacting proteins. Cloning is simplified by introduction of λ attachment sites for GATEWAY. Homo- and heteromeric interactions between Arabidopsis K + channels KAT1, AKT1, and AKT2 were identified. Tests with deletion mutants demonstrate that the C terminus of KAT1 and AKT1 is necessary for physical assembly of complexes. Screening of a sorted collection of 84 plant proteins with K + channels as bait revealed differences in oligomerization between KAT1, AKT1, and AtKC1, and allowed detection of putative interacting partners of KAT1 and AtKC1. These results show that mbSUS is suited for systematic analysis of membrane protein interactions.
Signals of Confinement in Green Functions of SU(2) Yang-Mills Theory
2004-08-06

It has been well established that the removal of center vortices from SU(2) lattice configurations results in the loss of confinement. The running coupling constant, gluon form factor, and ghost form factor are studied in the Landau gauge for the full and the vortex removed theory. In the latter case, a strong suppression of the running coupling constant and the gluon form factor at low momenta is observed, and the IR singularity of the ghost form factor disappears. Hence, the removal of the vortices generates a theory for which Zwanziger's horizon condition for confinement is no longer satisfied.
Studies of orbital parameters and pulse profile of the\\n accreting millisecond pulsar XTE J1807–294
2004-08-06

\\n The accreting millisecond pulsar XTE J1807-294 was observed as \\na Target of Opportunity (ToO) by XMM-Newton on March 22, 2003 after its\\ndiscovery on February 21, 2003 by RXTE .\\nThe source was detected in its bright phase with an observed average count\\nrate of 33.3 cts s-1 in the EPIC-pn camera in the 0.5–10 keV energy\\nband (3.7 mCrab). Using the earlier established best-fit\\norbital period of 40.0741 ± 0.0005 min from the RXTE observations and \\nconsidering a circular binary orbit as first approximation, we derived a\\nvalue of 4.8 ± 0.1 lt-ms for the projected orbital radius of the binary system and \\nan epoch of the orbital phase of MJD 52 720.67415(16). The barycentric \\nmean spin period of the pulsar was derived as 5.2459427 ± 0.0000004 ms. \\nThe pulsar's spin-pulse profile showed a prominent (1.5 ms FWHM) \\npulse, with energy and orbital phase\\ndependence in the amplitude and shape.\\nThe measured pulsed fraction in four energy bands was found to be 3.1 ± 0.2% (0.5–3.0 keV), \\n5.4 ± 0.4% (3.0–6.0 keV),\\n5.1 ± 0.7% (6.0–10.0 keV) and 3.7 ± 0.2% (0.5–10.0 keV), \\nrespectively.\\nStudies of spin-profiles with orbital phase and energy showed significant\\nincrease in its pulsed fraction during the second observed orbit of the\\nneutron star, gradually declining in the subsequent two orbits, which was\\nassociated with sudden but marginal increase in mass accretion.\\nFrom our investigations of orbital parameters and\\nestimation of other properties of this compact binary system, \\nwe conclude that XTE J1807-294 is very likely a candidate for a millisecond\\nradio pulsar.\\n\\n \\n
Lateral interactions in the perception of flicker and in the physiology of the lateral geniculate nucleus
2004-08-09

The perception of flicker strength in a center stimulus can be affected by the presence of a surrounding stimulus. We correlated this effect with the interactions between centers and surrounds of the receptive fields (RFs) of neurons in the retino-geniculate pathways. The responses of cells in the lateral geniculate nucleus (LGN) of two New World monkey species, the common marmoset (Callithrix jacchus), and the owl monkey (Aotus azarae) were measured to two spatially non-overlapping sinusoidally modulating luminance stimuli of equal temporal frequency, one of which mainly stimulated the RF center, the other the RF surround. The relative temporal phase between the center and surround stimuli was varied. The response amplitude as a function of relative phase between the center and surround stimuli can be described by a simple model where the RF center and surround responses are vector-added. A minimal response was reached for stimuli in which the surround stimulus led the center stimulus, indicating that the RF surround response lagged the center response. The flicker strength in the center stimulus perceived by human observers was measured psychophysically. It was found that the perceived flicker strength could be described by the same function as was used for the cell data. There were qualitative similarities between the physiological and the psychophysical data, suggesting that the physiological basis of the psychophysically measured spatial interactions is present as early as the LGN. The data indicated the presence of a nonlinearity in center-surround interactions that is influenced by the stimulus contrast. The possible source of this nonlinearity was studied by comparing the center and the surround responses with those in which they were selectively stimulated.
Molecular Electrochemistry of Cyclophanes
2004-08-09

This chapter contains sections titled: Introduction Electron Transfer and Molecular Electrochemistry Molecular Electrochemistry of Cyclophanes Methods of Molecular Electrochemistry Molecular Electrochemistry of Hydrocarbon Cyclophanes Molecular Electrochemistry of Functionalized Cyclophanes Substituted Cyclophanes Cyclophanes with Non-metallic Heteroatoms as Ring Members Molecular Electrochemistry of Organometallic Cyclophane Derivatives A Possible Classification of Organometallic Cyclophane Derivatives Metallocenophanes and Metallametallocenophanes Cyclophanes as π-Complex Ligands Cyclophanes as Supramolecular Components Conclusions References
Ab Initio NMR Spectra for Molecular Systems with a Thousand and More Atoms: A Linear‐Scaling Method
2004-08-11

A method for the calculation of NMR shieldings is presented, which allows for the first time the study of molecular systems with one thousand and more atoms at the ab initio level (see picture), by reducing the computational scaling from cubic to linear. This opens new possibilities for the often difficult assignment of experimental NMR spectra.
Synergistic effect of SU11248 with cytarabine or daunorubicin on FLT3 ITD–positive leukemic cells
2004-08-11

Abstract Fetal liver tyrosine kinase 3 internal tandem duplication (FLT3 ITD) mutations are the most common molecular abnormality associated with adult acute myeloid leukemia (AML). To exploit this molecular target, a number of potent and specific FLT3 kinase inhibitors have been developed and are currently being tested in early phase clinical trials of patients with refractory AML. To explore the efficacy of combining a FLT3 inhibitor with standard AML chemotherapy drugs, we tested the effect of combining the FLT3 inhibitor SU11248 with cytarabine or daunorubicin on the proliferation and survival of cell lines expressing either mutant (FLT3 ITD or FLT3 D835V) or wild-type (WT) FLT3. SU11248 had additive-to-synergistic inhibitory effects on FLT3-dependent leukemic cell proliferation when combined with cytarabine or daunorubicin. The synergistic interaction of SU11248 and the traditional antileukemic agents was more pronounced for induction of apoptosis. SU11248 inhibited the proliferation of primary AML myeloblasts expressing mutant FLT3 ITD but not WT FLT3 protein. Combining SU11248 and cytarabine synergistically inhibited the proliferation of primary AML myeloblasts expressing FLT3 ITD but not WT FLT3 protein. These data suggest that the addition of potent FLT3 inhibitors such as SU11248 to AML chemotherapy regimens could result in improved treatment results.
A simple molecule with a complex crystal structure: interplay of 31P solid‐state NMR spectroscopy and single‐crystal x‐ray diffraction in the structure determination of a ruthenium diphosphine diamine complex
2004-08-11

Abstract A comprehensive 31 P solid‐state NMR study of Ru(η 1 ‐Ph 2 PCH 2 CH 2 OCH 3 ) 2 (η 2 ‐en)Cl 2 (en = ethylenediamine) (1) , by 1D (contact time variation, inversion–recovery, SPARTAN) and 2D techniques (homonuclear J ‐resolved, SECSY) indicated that the crystal structure of 1 should be complex. The single‐crystal x‐ray structure determination confirmed the presence of eight independent molecules in the asymmetric unit, with 31 P isotropic chemical shifts in the range 27.3–40.1 ppm, while the spans of the phosphorus chemical shift tensors are of the order of 170 ppm. Based on unique structural features and NMR data, one molecule has been tentatively assigned. Copyright © 2004 John Wiley &amp; Sons, Ltd.
Discovery of kilogauss magnetic fields in three DA white dwarfs
2004-08-12

\\n We have detected longitudinal magnetic fields between 2 and 4 kG in three \\n(<ext-link ext-link-type="aoi">WD 0446-790</ext-link>, <ext-link ext-link-type="aoi">WD 1105-048</ext-link>, <ext-link ext-link-type="aoi">WD 2359-434</ext-link>) out \\nof a sample of 12 normal DA white dwarfs by using optical spectropolarimetry \\ndone with the VLT Antu 8 m telescope equipped with FORS1. With the exception \\nof 40 Eri B (4 kG) these are the first positive detections of magnetic fields \\nin white dwarfs below 30 kG. Although suspected, it was not clear whether a \\nsignificant fraction of white dwarfs contain magnetic fields at this level. \\nThese fields may be explained as relics from magnetic fields in the \\nmain-sequence progenitors considerably enhanced by magnetic flux conservation \\nduring the shrinkage of the core. A detection rate of 25% (3/12) may \\nindicate now for the first time that a substantial fraction of white dwarfs \\nhave a weak magnetic field. This result, if confirmed by future observations, \\nwould form a cornerstone for our understanding of the evolution of stellar \\nmagnetic fields.\\n\\n
Scotland and Nationalism
2004-08-12

Scotland and Nationalism provides an authoritative survey of Scottish social and political history from 1707 to the present day. Focusing on political nationalism in Scotland, Christopher Harvie examines why this nationalism remained apparently in abeyance for two and a half centuries, and why it became so relevant in the second half of the twentieth century.This fourth edition brings the story and historiography of Scottish society and politics up-to-date. Additions also include a brand new biographical index of key personalities, along with a glossary of nationalist groups.