julilili42/papers huggingface dataset:
Spatial compatibility between stimulated eye and response location
2007-10-26

Abstract It is assumed that the eye‐of‐origin information is restricted to the visual cortex. However, reactions to monocular stimuli are faster when the response location and the stimulated eye are ipsilateral (compatible trials) than when they are contralateral (incompatible trials). We investigated whether this spatial compatibility effect had the characteristics of the conventional visual Simon effect. We found that the size of the compatibility effect was constant throughout the reaction time distribution, and there were no electrophysiological signs of incorrect response activation. These results indicate that the spatial code derived from eye‐of‐origin information does not produce a transient activation of the spatially compatible response, but a more tonic influence on response selection. The results also show that monocular information can exert influence outside the visual cortex and that spatial codes can be produced in the absence of attention movements.
Spinocerebellar ataxia type 7 (SCA7): widespread brain damage in an adult‐onset patient with progressive visual impairments in comparison with an adult‐onset patient without visual impairments
2007-10-28

Spinocerebellar ataxia type 7 (SCA7) represents a rare and severe autosomal dominantly inherited ataxic disorder and is among the known CAG‐repeat, or polyglutamine, diseases. In contrast to other currently known autosomal dominantly inherited ataxic disorders, SCA7 may manifest itself with different clinical courses. Because the degenerative changes evolving during these different clinical courses are not well known, many neurological disease symptoms still are unexplained. We performed an initial pathoanatomical study on unconventional thick tissue sections of the brain of a clinically diagnosed and genetically confirmed adult‐onset SCA7 patient with progressive visual impairments. In this patient we observed loss of myelinated fibres in distinct central nervous fibre tracts, and widespread degeneration of the cerebellum, telencephalon, diencephalon and lower brainstem. These degenerative changes offer appropriate explanations for a variety of less‐understood neurological symptoms in adult‐onset SCA7 patients with visual impairments: gait, stance and limb ataxia, falls, dysarthria, dysphagia, pyramidal signs, Parkinsonian features, writing problems, impairments of saccades and smooth pursuits, altered pupillary functions, somatosensory deficits, auditory deficits and mental impairments.
MR elastography of breast lesions: Understanding the solid/liquid duality can improve the specificity of contrast‐enhanced MR mammography
2007-10-29

Abstract The purpose of this analysis is to explore the potential diagnostic gain provided by the viscoelastic shear properties of breast lesions for the improvement of the specificity of contrast enhanced dynamic MR mammography (MRM). The assessment of viscoelastic properties is done via dynamic MR elastography (MRE) and it is demonstrated that the complex shear modulus of in vivo breast tissue follows within the frequency range of clinical MRE a power law behavior. Taking benefit of this frequency behavior, data are interpreted in the framework of the exact model for wave propagation satisfying the causality principle. This allows to obtain the exponent of the frequency power law from the complex shear modulus at one single frequency which is validated experimentally. Thereby, scan time is drastically reduced. It is observed that malignant tumors obtain larger exponents of the power law than benign tumors indicating a more liquid‐like behavior. The combination of the Breast Imaging Reporting and Data System (BIRADS) categorization obtained via MRM with viscoelastic information leads to a substantial rise in specificity. Analysis of 39 malignant and 29 benign lesions shows a significant diagnostic gain with an increase of about 20% in specificity at 100% sensitivity. Magn Reson Med, 2007. © 2007 Wiley‐Liss, Inc.
Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation
2007-10-29

The Landau-Lifshitz-Gilbert equation describes magnetic behavior in ferromagnetic materials. Construction of numerical strategies to approximate weak solutions for this equation is made difficult by its top order nonlinearity and nonconvex constraint. In this paper, we discuss necessary scaling of numerical parameters and provide a refined convergence result for the scheme first proposed by Alouges and Jaisson (2006). As an application, we numerically study discrete finite time blowup in two dimensions.
Detection of DNA double‐strand breaks using γh2AX after MRI exposure at 3 Tesla: An in vitro study
2007-10-29

Abstract Purpose To evaluate the effects of the static magnetic field and typical imaging sequences of a high‐field magnetic resonance scanner (3 Tesla) on the induction of double‐strand breaks (DSBs) in two different human cell lines. Materials and Methods Human promyelocytic leukemia cells (HL‐60) and human acute myeloid leukemia cells (KG‐1a) were exposed to the static magnetic field alone and to turbo spin‐echo (TSE) and gradient‐echo (GE) sequences. Flow cytometry was used to quantify γH2AX (serine 139 phosphorylated form of histone H2AX) expression of antibody‐stained cells as a marker for deoxyribonucleic acid (DNA) DSBs one hour and 24 hours after magnetic field exposure. X‐ray–treated cells were used as positive control. Results Neither exposure to the static magnetic field alone nor to the applied imaging sequences showed significant differences in γH2AX expression between exposed and sham‐exposed cells. X‐ray–treated cells as positive control showed a significant increase in γH2AX expression. Conclusion The static magnetic field alone and MRI sequences at 3 Tesla have no effect on the induction of DSBs in HL‐60 and KG‐1a cells. J. Magn. Reson. Imaging 2007;26:1308–1314. © 2007 Wiley‐Liss, Inc.
Navigator‐triggered oxygen‐enhanced MRI with simultaneous cardiac and respiratory synchronization for the assessment of interstitial lung disease.
2007-10-29

Abstract Purpose To evaluate an optimized method for oxygen‐enhanced MRI of the lung, using simultaneous electrocardiograph (ECG) and navigator triggering. To correlate oxygen‐enhanced MRI with lung function tests assessing alveolar‐capillary gas exchange. Materials and Methods A total of 12 healthy volunteers (aged 20–32 years) and 10 patients (aged 37–87 years) with interstitial lung diseases (ILD) underwent oxygen‐enhanced MRI and pulmonary functional tests (PFTs) assessing alveolar‐capillary gas exchange. The paradigm room‐air–oxygen–room‐air was acquired with a nonselective inversion‐recovery half‐Fourier single‐shot turbo spin‐echo sequence (inversion time = 1200 msec; acquisition time = 134.5 msec; slice thickness = 20 mm; matrix size = 128 × 128), using simultaneous double triggering (navigator plus ECG trigger). Cross‐correlation was performed in regions of interest (ROIs) encompassing both lungs. The number of oxygen‐activated pixels over the total number of pixels in the ROIs (OAP%) of volunteers and patients was compared. OAP%s were correlated with PFTs. Results The mean OAP% of patients was significantly lower than that of volunteers (36.7 vs. 81.7, P = 0.001). OAP% correlated with the transfer lung factor for carbon monoxide (Tlco) (r = 0.64; P = 0.002), the transfer coefficient (Kco) (r = 0.75; P = 0.001), the arterial partial pressure (r = 0.77; P &lt; 0.001), and the saturation (r = 0.70; P &lt; 0.001) of oxygen. Conclusion Navigator‐triggered oxygen‐enhanced MRI of the lung may have a potential role in the quantitative assessment of lung function in ILD. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Tissue warming and regulatory responses induced by radio frequency energy deposition on a whole‐body 3‐Tesla magnetic resonance imager
2007-10-29

Abstract Purpose To quantify the B1‐field induced tissue warming on a 3T‐whole‐body scanner, to test whether the patient is able to sense the temperature change, and to evaluate whether the imaging procedure constitutes a significant cardiovascular stress. Materials and Methods A total of 18 volunteers were divided into three equal groups for 3.0T MRI of the pelvis, the head, or the knee. An imaging protocol operating at first level mode was applied, allowing radio frequency (RF) irradiation up to the legal specific absorption rate (SAR) limits. An identical placebo protocol with active gradient switching but without RF transmission was used. Temperature changes were measured with a fiber‐optic thermometer (FO) and an infrared camera (IR). Results Temperature differences to the placebo were highest for imaging of the pelvis (FO: ΔT = 0.88 ± 0.13°C, IR: ΔT = 1.01 ± 0.15°C) as compared to the head (FO: ΔT = 0.46 ± 0.12°C, IR: ΔT = 0.47 ± 0.10°C) and the knee (FO: ΔT = 0.33 ± 0.11°C, IR: ΔT = 0.37 ± 0.09°C). The volunteers were able to discriminate between imaging and placebo for pelvic ( P &lt; 0.0001) and head ( P = 0.0005) imaging but not for knee imaging ( P = 0.209). No changes in heart rate or blood pressure were detected. Conclusion The 3.0T MRI in the first operational mode may lead to measurable and perceptible thermal energy deposition. However, it may be regarded as safe concerning the thermoregulatory cardiovascular stress. J. Magn. Reson. Imaging 2007;26:1334–1339. © 2007 Wiley‐Liss, Inc.
Do static or time‐varying magnetic fields in magnetic resonance imaging (3.0 T) alter protein–gene expression?—A study on human embryonic lung fibroblasts
2007-10-29

Abstract Purpose To evaluate the influence of magnetic resonance imaging (MRI) on gene expression in embryonic human lung fibroblasts (Hel 299). Materials and Methods The cells were exposed to the static magnetic field and to a turbo spin‐echo sequence of an MR scanner at 3.0 Tesla. An MR group (exposed) and a control group (sham‐exposed) were set up using a special MR‐compatible incubation system. The exposure time was two hours. Gene expression profiles were studied using a complementary deoxyribonucleic acid (cDNA) microarray containing 498 known genes involved in transcription, intracellular transport, structure/junction/adhesion or extracellular matrix, signaling, host defense, energetics, metabolism, cell shape, and death. Results No changes in gene expression were found in either group (exposed or sham‐exposed cells) at the end of a two‐hour exposure for any of the 498 tested protein genes. Conclusion The results suggest that MRI has no influence on protein–gene expression in eugenic human lung cells. J. Magn. Reson. Imaging 2007;26:1210–1215. © 2007 Wiley‐Liss, Inc.
A TREE-HEIGHT HIERARCHY OF CONTEXT-FREE LANGUAGES
2007-10-29

We consider the minimal height of a derivation tree as a complexity measure for context-free languages and show that this leads to a strict and dense hierarchy between logarithmic and linear (arbitrary) tree height. In doing so, we improve a result obtained by Gabarro in [7]. Furthermore, we provide a counter-example to disprove a conjecture of Čulik and Maurer in [6] who suggested that all languages with logarithmic tree height would be regular. As a new method, we use counter-representations where the successor relation can be handled as the complement of context-free languages. A similar hierarchy is obtained considering the ambiguity as a complexity measure.
NMR Relaxation and Resistivity from Rattling Phonons in Pyrochlore Superconductors
2007-10-30

We calculate the temperature dependence of the NMR relaxation rate and electrical resistivity for coupling to a local, strongly anharmonic phonon mode. We argue that the two-phonon Raman process is dominating NMR relaxation. Due to the strong anharmonicity of the phonon an unusual temperature dependence is found having a low temperature peak and becoming constant towards higher temperatures. The electrical resistivity is found to vary like T2 at low temperatures and following a square root T behavior at high temperatures. Both results are in qualitative agreement with recent observations on beta-pyrochlore oxide superconductors.
Comparing Natural and Constrained Movements: New Insights into the Visuomotor Control of Grasping
2007-10-30

The demonstration that activity within the hAIPS is modulated according to different types of grasp, together with the evidence in humans that the dorsal premotor cortex is involved in grasp planning and execution offers a substantial contribution to the current debate about the neural substrates of visuomotor grasp in humans.
Oxidation induces ClC‐3‐dependent anion channels in human leukaemia cells
2007-10-30

To test for redox regulation of anion channels in erythroid cells, we exposed K562 cells to oxidants and measured changes in transmembrane Cl − currents using patch‐clamp, and in intracellular Cl − content using the Cl − selective dye MQAE. Oxidation with tert ‐butylhydroperoxide or H 2 O 2 produced a plasma membrane anion permeability with a permselectivity of urn:x-wiley:00145793:media:feb2s0014579307011076:feb2s0014579307011076-math-si2 The permeability increase was paralleled by insertion of ClC‐3 protein into the plasma membrane as evident from immunofluorescence microscopy and surface biotinylation. Down‐regulation of ClC‐3 protein by RNA interference as assessed by immunoblotting decreased the oxidation‐stimulated permeability. In conclusion, oxidation induces surface expression of ClC‐3 and activation of a ClC‐3‐dependent anion permeability in K562 cells.
An Evolutionary Model of Racial Attitude Formation: Socially Shared and Idiosyncratic Racial Attitudes
2007-10-30

A growing body of research in political science has uncovered evidence of a “split personality” among Americans when it comes to racial attitudes—people express different attitudes in public than they personally hold. At present no theoretical model can account for the emergence of this discrepancy. This article proposes a simple neural model of racial attitude formation that makes an important distinction between socially shared and idiosyncratic racial attitudes. A computational model based on Kimura's (1983) Neutral Theory of Evolution predicts that socially shared racist attitudes may be able to coexist with, and eventually be replaced by, more favorable idiosyncratic racial attitudes. Results of a laboratory-based study ( N = 555) involving reaction-time-based implicit measures of socially shared and idiosyncratic attitudes are consistent with the predictions derived from the computational model. The implications of the theoretical model and the empirical findings are discussed.
2007-10-30

The biosynthesis of leukotrienes (LTs) is initiated by the transformation of free arachidonic acid to LTA 4 by 5-lipoxygenase (5-LO).Subsequent enzymatic conversion of LTA 4 yields LTB 4 and the cysteinyl-LTs C 4 , D 4 and E 4 .LTs have prominent functions in pathophysiology and are connected to numerous disorders including bronchial asthma, allergic rhinitis, inflammatory bowel and skin diseases, rheumatoid arthritis, cancer, osteoporosis and cardiovascular diseases.Pharmacological and genetic interruption of the 5-LO pathway or blockade of LT receptors, serving as means for intervention with LTs, may be of therapeutic value for certain related disorders.Natural or plant-derived substances were among the first 5-LO inhibitors identified in the early 1980 s. To date, a huge number of diverse plant-derived compounds have been reported to interfere with 5-LO product synthesis.However, many investigations have addressed the efficacy of a given compound solely in cellular test systems and analysis of direct interference with 5-LO has been neglected.In the first part of this review, the biology and molecular pharmacology of the 5-LO pathway is summarized in order to understand its overall regulation and complexity as well as to comprehend the possible points of attack of compounds that eventually lead to inhibition of 5-LO product formation in intact cells.In the second part, natural compounds that interfere with 5-LO product formation are compiled and grouped into structural classes, and the underlying molecular mechanisms and structureactivity relationships are discussed.
Antidepressant effects of augmentative transcranial magnetic stimulation
2007-10-31

Background Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a new treatment option for depression. Previous studies were performed with low sample sizes in single centres and reported heterogeneous results. Aims To investigate the efficacy of rTMS as augmentative treatment in depression. Method In a randomised, double-blind, sham-controlled multicentre trial 127 patients with moderate to severe depressive episodes were randomly assigned to real or sham stimulation for 3 weeks in addition to simultaneously initiated antidepressant medication. Results We found no difference in the responder rates of the real and the sham treatment groups (31% in each) or in the decrease of the scores on the depression rating scales. Conclusions The data do not support previous reports from smaller samples indicating an augmenting or accelerating antidepressant effect of rTMS. Further exploration of the possible efficacy of other stimulation protocols or within selected sub-populations of patients is necessary.
Expeditious Synthesis of Glycosylated Phthalocyanines.
2007-10-31

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Some Ethyl 3‐(Aryldiazenyl)‐7‐oxo‐dihydropyrido[2,3‐f]quinoxaline‐8‐carboxylates.
2007-10-31

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Investigation of Molecular Transfer Processes across Phospholipid Monolayers by the Combined Scanning Electrochemical Microscopy-Langmuir Trough Technique
2007-10-31

Scanning electrochemical microscopy (SECM) has emerged as a powerful techniquefor inducing and monitoring molecular transfer processes across water/air and liquid/liquid interfaces. At the same time, the Langmuir trough technique is a well established method for controlling the lateral pressure of molecular films of amphiphilic molecules at interfaces. A combination of both methods allows the investigation of the permeability of monolayers in a defined state. A brief introduction of the SECM technique and the experimental set-up is presented. The application of the combined SECM- Langmuir trough technique to measure passive diffusion of small molecules (O2 and Br2) across phospholipid monolayers is then reviewed. Phospholipid monolayers at liquid/liquid and liquid/air interfaces serve as simple biomimetic models for biomembranes and the results of the combined SECM- Langmuir trough measurements have implications for understanding passive diffusion across cellular membranes.
Concise Review: Isolation and Characterization of Cells from Human Term Placenta: Outcome of the First International Workshop on Placenta Derived Stem Cells
2007-11-01

Abstract Placental tissue draws great interest as a source of cells for regenerative medicine because of the phenotypic plasticity of many of the cell types isolated from this tissue. Furthermore, placenta, which is involved in maintaining fetal tolerance, contains cells that display immunomodulatory properties. These two features could prove useful for future cell therapy-based clinical applications. Placental tissue is readily available and easily procured without invasive procedures, and its use does not elicit ethical debate. Numerous reports describing stem cells from different parts of the placenta, using nearly as numerous isolation and characterization procedures, have been published. Considering the complexity of the placenta, an urgent need exists to define, as clearly as possible, the region of origin and methods of isolation of cells derived from this tissue. On March 23–24, 2007, the first international Workshop on Placenta Derived Stem Cells was held in Brescia, Italy. Most of the research published in this area focuses on mesenchymal stromal cells isolated from various parts of the placenta or epithelial cells isolated from amniotic membrane. The aim of this review is to summarize and provide the state of the art of research in this field, addressing aspects such as cell isolation protocols and characteristics of these cells, as well as providing preliminary indications of the possibilities for use of these cells in future clinical applications. Disclosure of potential conflicts of interest is found at the end of this article.
Analysis of Efficacy and Failure in Proximal Humerus Fractures Treated With Locking Plates
2007-11-01

This series presents the experience using PHLP in 5 Level 1 trauma centers. There were no intraoperative complications related to the locking plate systems. Despite the use of fixed-angle devices, loss of fixation occurred, primarily in the presence of varus malreduction. Our findings suggest that avoiding varus should substantially decrease the risk of postoperative failures.
Identification of HLA-DR–bound peptides presented by human bronchoalveolar lavage cells in sarcoidosis
2007-11-01

Sarcoidosis is an inflammatory disease of unknown etiology, most commonly affecting the lungs. Activated CD4+ T cells accumulate in the lungs of individuals with sarcoidosis and are considered to be of central importance for inflammation. We have previously shown that Scandinavian sarcoidosis patients expressing the HLA-DR allele DRB1*0301 are characterized by large accumulations in the lungs of CD4+ T cells expressing the TCR AV2S3 gene segment. This association afforded us a unique opportunity to identify a sarcoidosis-specific antigen recognized by AV2S3+ T cells. To identify candidates for the postulated sarcoidosis-specific antigen, lung cells from 16 HLA-DRB1*0301pos patients were obtained by bronchoalveolar lavage. HLA-DR molecules were affinity purified and bound peptides acid eluted. Subsequently, peptides were separated by reversed-phase HPLC and analyzed by liquid chromatography-mass spectrometry. We identified 78 amino acid sequences from self proteins presented in the lungs of sarcoidosis patients, some of which were well-known autoantigens such as vimentin and ATP synthase. For the first time, to our knowledge, we have identified HLA-bound peptides presented in vivo during an inflammatory condition. This approach can be extended to characterize HLA-bound peptides in various autoimmune settings.
Repeated treatment with the NMDA antagonist MK-801 disrupts reconsolidation of memory for amphetamine-conditioned place preference
2007-11-01

Long-lasting drug-associated memories can contribute to relapse; therefore these memories must be inactivated to enable sustainable success in addiction therapy. As drug associations are usually acquired over several conditioning events, we assume that an effective treatment should be repeatedly applied to achieve persistent effects. In this study, we examine whether 10 repeated memory reactivation tests followed by systemic N-methyl-D-aspartate receptor antagonist MK-801 (0.1 mg/kg) administrations can disrupt memory reconsolidation in rats, leading to a reduction of well-established amphetamine-conditioned place preference (CPP). We found that immediate (but not 60-min delayed) administration of MK-801 after the tests reduced amphetamine-CPP expression after at least four treatments. These effects were specific to CPP expression as no MK-801-induced change in locomotion was observed during all tests. We discuss these results as being caused by MK-801 disrupting memory reconsolidation and we propose the applied repeated-treatment regimen as a new therapeutic research strategy to persistently disrupt drug-associated memories.