julilili42/papers huggingface dataset:
Electron transport in pristine and alkali metal doped perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA) thin films
2006-09-20

The controlled adjustment of the conductivity of molecular organic semiconductors is essential for their technical application. As the -type organic semiconductor perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA) is known to be doped by alkali metals, pristine and sodium doped PTCDA was chosen as a model system to investigate the charge carrier generation and transport in organic semiconductors. Temperature-dependent conductivity measurements were performed to obtain information about the transport mechanism. Measurement of the thermoelectric force, i.e., the Seebeck coefficient, gives a closer insight into the energy levels, participating in charge carrier generation. Based on the performed measurements a model for charge carrier transport in pristine and in alkali metal doped PTCDA is suggested.
Cord Blood Dendritic Cell Subsets in African Newborns Exposed toPlasmodium falciparumIn Utero
2006-09-20

ABSTRACT Placental Plasmodium falciparum infection affects birth outcomes and sensitizes fetal lymphocytes to parasite antigens. We assessed the influence of maternal P. falciparum infection on fetal myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC), analyzing the cord blood of offspring of Gabonese mothers with different infection histories. Cord blood from newborns of mothers with malarial infection at delivery had significantly more mDC than that from nonexposed newborns ( P = 0.028) but mDC and pDC HLA-DR expression was unrelated to maternal infection history. Independently of these findings, cord blood mDC and pDC numbers declined significantly as a function of increasing maternal age ( P = 0.029 and P = 0.033, respectively). The inducible antigen-specific interleukin-10-producing regulatory-type T-cell population that we have previously detected in cord blood of newborns with prolonged in utero exposure to P. falciparum may directly reflect the altered DC numbers in such neonates, while the maintenance of cord blood DC HLA-DR expression contrasts with that of DC from P. falciparum malaria patients.
Molecular and functional changes of pulmonary surfactant in response to hyperoxia
2006-09-20

Abstract Surfactant comprises phosphatidylcholine (PC) together with anionic phospholipids, neutral lipids, and surfactant proteins SP‐A to‐D. Its composition is highly specific, with dipalmitoyl‐PC, palmitoyl‐myristoyl‐PC, and palmitoyl‐palmitoleoyl‐PC as its predominant PC species, but with low polyunsaturated phospholipids. Changes in pulmonary metabolism and function in response to injuries depend on their duration and whether adaptation can occur. We examined in rats prolonged (7 days) versus acute (2 days) exposure to non‐lethal oxygen concentrations (85%) with respect to the composition and metabolism of individual lung phospholipid molecular species. Progressive inflammation, structural alteration, and involvement of type II pneumocytes were confirmed by augmented bromodeoxyuridine incorporation, broadening of alveolar septa, and increased granulocyte, macrophage, SP‐A, and SP‐D concentrations. Surfactant function was impaired after 2 days, but normalized with duration of hyperoxia, which was attributable to inhibition but not to alteration in SP‐B/C concentrations. Phospholipid pool sizes and PC synthesis by lung tissue, as assessed by [methyl‐ 3 H]‐choline incorporation, were unchanged after 2 days, although after 7 days they were elevated 1.7‐fold. By contrast, incorporation of labeled PC into tissue pools of surfactant and lung lavage fluid decreased progressively. Moreover, concentrations of arachidonic acid containing phospholipids were augmented at the expense of saturated palmitoyl‐myristoyl‐PC and dipalmitoyl‐PC. We conclude a persisting impairment in the intracellular trafficking and secretion of newly synthesized PC, accompanied by a progressive increase in alveolar arachidonic acid containing phospholipids in spite of recovery of acutely impaired surfactant function and adaptive increase of overall PC synthesis. Pediatr Pulmonol. 2006, 41:1025–1039. © 2006 Wiley‐Liss, Inc.
Differing activation status and immune effector molecule expression profiles of neonatal and maternal lymphocytes in an African population
2006-09-20

Summary Higher susceptibility of newborns to infections has been attributed to the hypo‐responsiveness of their cellular immune system. Here we compared the activation status and expression of cytokines and cytotoxic molecules of cord versus maternal peripheral blood mononuclear cells in an African population. Human leucocyte antigen‐DR was expressed on a lower percentage of cord compared to maternal γδ and CD3 + T cells. Similarly, a lower proportion of cord versus maternal γδ and CD3 + T cells displayed perforin, granzyme B and cytokine activity either ex vivo or following non‐specific stimulation in vitro . In contrast, comparable proportions of cord and maternal CD94 + CD3 – natural killer (NK) cells showed perforin and granzyme B expression ex vivo . We conclude that cord blood γδ and CD3 + T cells are functionally hypo‐responsive as reflected by reduced numbers of such cells expressing either an activation marker, T helper 1 (Th1) and Th2 cytokines or cytotoxic effector molecules. The similarity in numbers of cord and maternal CD94 + CD3 – cells expressing cytotoxic effector molecules suggests that neonatal Africans' NK cells may be functionally mature.
Impact of short‐term versus longterm topical steroid treatment on ‘idiopathic’ endothelial cell loss after normal‐risk penetrating keratoplasty
2006-09-20

Abstract. Purpose: Chronic endothelial cell loss after penetrating keratoplasty (PK) is suspected to result from a subclinical immune reaction. The aim of this study was to investigate whether the prolonged use of a topical steroid after normal‐risk PK has a favourable impact on chronic endothelial cell loss. Methods: The study included 305 eyes from the prospective Erlangen Normal‐risk Keratoplasty Study, with a mean follow‐up of 3.1 ± 0.9 years. Postoperative treatment was initiated with prednisolone acetate 1% eyedrops five times a day and was tapered slowly over the first 6 months. Patients were then randomized into two treatment groups: a short‐term group ( n = 161), which stopped topical steroid treatment, and a longterm group ( n = 144), which continued topical treatment with prednisolone acetate 1% eyedrops once a day until 12 months postoperatively. Endothelial cell counts were determined at each follow‐up examination (after 6 weeks, then every 3 months until 2 years, then once a year). Results: Endothelial cell density in the short‐term and longterm groups decreased significantly from 1941 ± 550 cells/mm 2 and 1957 ± 568 cells/mm 2 to 1535 ± 535 cells/mm 2 and 1472 ± 549 cells/mm 2 , respectively, from 6 weeks to 2 years postoperatively (p &lt; 0.001). In a linear regression model, cell count in the short‐term group decreased by 216 ± 93 cells/mm 2 and in the longterm group by 206 ± 111 cells/mm 2 per year. There was no significant difference in endothelial cell loss between the short‐term and longterm groups (p = 0.5). Conclusions: Longterm, low‐dose, topical steroid treatment does not seem to prohibit chronic endothelial cell loss after normal‐risk penetrating keratoplasty, in contrast to its favourable effect on immunological graft reactions. Our results may indicate that the aetiology of chronic endothelial cell loss is not of inflammatory origin. Further studies are needed to investigate this phenomenon.
Valproic acid induced pancreatitis: 16 new cases and literature overview
2006-09-20

Valproic acid (VPA) is a commonly prescribed medication for generalized and focal epilepsy, migraine, neuropathic pain and bipolar disorder. The common side effects associated with VPA are typically benign, less common but more serious adverse effects may occur. These include hepatotoxicity, hyperammonemic encephalopathy, coagulation disorders and pancreatitis. Since 1979, a few cases of pancreatitis induced by VPA have been published in the medical literature.
SLICK — Scoring and Energy Functions for Protein—Carbohydrate Interactions.
2006-09-20

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.
Exogenous Induction of Cerebral ß-Amyloidogenesis Is Governed by Agent and Host
2006-09-21

Protein aggregation is an established pathogenic mechanism in Alzheimer's disease, but little is known about the initiation of this process in vivo. Intracerebral injection of dilute, amyloid-β (Aβ)–containing brain extracts from humans with Alzheimer's disease or β-amyloid precursor protein (APP) transgenic mice induced cerebral β-amyloidosis and associated pathology in APP transgenic mice in a time- and concentration-dependent manner. The seeding activity of brain extracts was reduced or abolished by Aβ immunodepletion, protein denaturation, or by Aβ immunization of the host. The phenotype of the exogenously induced amyloidosis depended on both the host and the source of the agent, suggesting the existence of polymorphic Aβ strains with varying biological activities reminiscent of prion strains.
Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions
2006-09-21

A new scheme for testing nuclear matter equations of state (EsoS) at high densities using constraints from neutron star phenomenology and a flow data analysis of heavy-ion collisions is suggested. An acceptable EoS shall not allow the direct Urca process to occur in neutron stars with masses below , and also shall not contradict flow and kaon production data of heavy-ion collisions. Compact star constraints include the mass measurements of 2.1 +/- 0.2 M_sun (1 sigma level) for PSR J0751+1807, of 2.0 +/- 0.1 M_sun from the innermost stable circular orbit for 4U 1636-536, the baryon mass - gravitational mass relationships from Pulsar B in J0737-3039 and the mass-radius relationships from quasiperiodic brightness oscillations in 4U 0614+09 and from the thermal emission of RX J1856-3754. This scheme is applied to a set of relativistic EsoS constrained otherwise from nuclear matter saturation properties with the result that no EoS can satisfy all constraints simultaneously, but those with density-dependent masses and coupling constants appear most promising.
MEMS Gas-Sensor Array for Monitoring the Perceived Car-Cabin Air Quality
2006-09-21

Microelectromechanical-system (MEMS) metal-oxide gas sensors have reached a mature stage, which makes mass market applications in the automotive area possible. In contrast to the already established flap-control system, which controls the access of (combustion) gases from outside the vehicle to the car cabin, the system studied here detects odor events created within the car cabin. The events under study have been cigarette smoke, fast-food odor, manure, and bioeffluents (flatulence). As the reference cannot be a "simple analytical measurement," a human test panel for assessing the hedonic impression on a scale from 0 to 5 is used as reference. The technical system is a MEMS metal-oxide-sensor array consisting of three different sensors. The data-evaluation approach used here is combining the human-sensory data and the MEMS sensor data. The task is performed by the combination of two independent algorithms, where one is related to the normalized conductance and the other to signal variance. Using a combined approach has the advantage that "false" events are suppressed. After the algorithm was successfully transferred onto a microcontroller, real-life data were recorded and classified. Several practical examples are given in this paper. The overall gas-sensor system reaches good accordance with the human-sensory impression, which is represented by air quality levels. This enables the design of a demand-controlled ventilation system.
Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes
2006-09-21

VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.
Reversed Pulmonary Artery Flow in Isolated Noncompaction of the Ventricular Myocardium
2006-09-21

&lt;i&gt;Objective:&lt;/i&gt; To investigate the morphology and genetics of a fetus at 22 weeks. This fetus demonstrated progressive fetal hydrops and cardiomegaly with retrograde flow in the pulmonary artery and progressive myocardial deterioration and heart failure. &lt;i&gt;Methods:&lt;/i&gt; Postmortem examination, light and electron microscopy of the myocardium, karyotyping, fetal DNA analysis, screening for mutations in the G4.5 gene, α-dystrobrevin gene, FKBP 12 gene, Desmin, Syntrophin and Cypher/ZASP genes, which have been described as being associated with noncompaction ventricular myocardium, using single-strand DNA conformation polymorphism analysis and DNA sequencing. &lt;i&gt;Results:&lt;/i&gt; The morphological diagnosis was compatible with noncompaction ventricular myocardium or spongyforme myopathy. The karyotype was normal. Mutation analysis in exons and introns of all six genes did not show any known mutation. &lt;i&gt;Conclusion:&lt;/i&gt; Noncompaction ventricular myocardium or spongyforme myopathy may be associated with mutations in genes which have previously not been thought to be associated with this phenotype. Alternatively, this disease could be the result of abnormal cardiac hemodynamics.
Automatic Calibration of Camera to World Mapping in RoboCup using Evolutionary Algorithms
2006-09-22

A common practical problem in mobile robotics is the task to calibrate the robot's sensors. Although, the general mapping of the sensor data to robot-centered world coordinates is given by the hardware configuration, the parameters of this mapping vary even between robots with the same configuration. In the RoboCup domain, these parameters can change drastically after transport or physical contact during game play. It is therefore necessary to recalibrate the robots for their next assignment within a few minutes, not only in order to fulfill the future regulatory requirements of the RoboCup organization committee to keep the setup time as low as possible. As camera systems, especially omni-directional systems, are currently the most important sensors in RoboCup, a reliable and fast calibration method for the mapping of image to world coordinates is necessary. Since the RoboCup environment, i.e. the soccer field, has known dimensions and is also static, automatic calibration using the features and landmarks of the soccer field is possible if the robot is given an image from a known pose. In this paper, an efficient evolutionary approach to automatic camera calibration is presented, which is independent of the hardware configuration. It only requires a quality function for the parameter settings, which allows lazy evaluation. To meet the time constraints given for this real-world optimization problem, a novel mutation operator is introduced to enhance the performance of the evolutionary algorithm. It samples a number of alternative solutions using a high rate of lazy evaluation, before deciding on the true mutative change applied on the given individual. This new mutation operator proves to be fast and most reliable on the camera to world calibration problem.
Relativistic self-energy in nuclear dynamics
2006-09-22

It is a well known fact that Dirac phenomenology of nuclear forces predicts the existence of large scalar and vector mean fields in matter. To analyse the relativistic self-energy in a model independent way, modern high precision nucleon-nucleon ( ) potentials are mapped on a relativistic operator basis using projection techniques. This allows to compare the various potentials at the level of covariant amplitudes were a remarkable agreement is found. It allows further to calculate the relativistic self-energy in nuclear matter in Hartree-Fock approximation. Independent of the choice of the nucleon-nucleon interaction large scalar and vector mean fields of several hundred MeV magnitude are generated at tree level. In the framework of chiral EFT these fields are dominantly generated by contact terms which occur at next-to-leading order in the chiral expansion. Consistent with Dirac phenomenology the corresponding low energy constants which generate the large fields are closely connected to the spin-orbit interaction in scattering. The connection to QCD sum rules is discussed as well.
Breaking the silence: Brain–computer interfaces (BCI) for communication and motor control
2006-09-25

Abstract Brain–computer interfaces (BCI) allow control of computers or external devices with regulation of brain activity alone. Invasive BCIs, almost exclusively investigated in animal models using implanted electrodes in brain tissue, and noninvasive BCIs using electrophysiological recordings in humans are described. Clinical applications were reserved with few exceptions for the noninvasive approach: communication with the completely paralyzed and locked‐in syndrome with slow cortical potentials, sensorimotor rhythm and P300, and restoration of movement and cortical reorganization in high spinal cord lesions and chronic stroke. It was demonstrated that noninvasive EEG‐based BCIs allow brain‐derived communication in paralyzed and locked‐in patients but not in completely locked‐in patients. At present no firm conclusion about the clinical utility of BCI for the control of voluntary movement can be made. Invasive multielectrode BCIs in otherwise healthy animals allowed execution of reaching, grasping, and force variations based on spike patterns and extracellular field potentials. The newly developed fMRI‐BCIs and NIRS‐BCIs, like EEG BCIs, offer promise for the learned regulation of emotional disorders and also disorders of young children.
Transition magnetic moments of Majorana neutrinos in supersymmetry withoutR-parity in light of neutrino oscillations
2006-09-25

The transition magnetic moments of Majorana neutrinos are calculated in grand unified theory (GUT) constrained Minimal Supersymmetric Standard Model (MSSM) with explicit R-parity violation. It is assumed that neutrinos acquire masses via one-loop (quark-squark and lepton-slepton) radiative corrections. The mixing of squarks, sleptons, and quarks is considered explicitly. The connection between neutrino magnetic moments and the entries of neutrino mass matrix is studied. The current upper limits on neutrino magnetic moments are deduced from the elements of phenomenological neutrino mass matrix, which is reconstructed using the neutrino oscillation data and the lower bound on the neutrinoless double beta decay half-life. Further, the results for transitional magnetic moments of Majorana neutrinos are presented for the cases of inverted and normal hierarchy of neutrino masses and different SUSY scenarios. The largest values are of the order of 10^{-17} in units of Bohr magneton.
Three-dimensional structure of laccase from Coriolus zonatus at 2.6 Å resolution
2006-09-25

Laccase (oxygen oxidoreductase, EC 1.14.18.1) belongs to the copper-containing oxidases. This enzyme catalyzes reduction of molecular oxygen by different organic and inorganic compounds to water without the formation of hydrogen peroxide. The three-dimensional structure of native laccase from Coriolus zonatus was solved and refined at 2.6 Å resolution (R factor = 21.23%, R free = 23.82%, rms deviations for the bond lengths and bond angles are 0.008 Å and 1.19°, respectively). The primary structure of the polypeptide chain and the architecture of the active site were refined. The carbohydrate component of the enzyme was identified. The access and exit water channels providing the access of molecular oxygen to the active site and release of water, which is the reduction product of molecular oxygen, from the protein molecule were found in the structure.
3.9 day orbital modulation in the TeV γ-ray flux and spectrum from the X-ray binary LS 5039
2006-09-26

Aims. LS 5039 is a High Mass X-ray Binary (HMXRB) comprising a compact object in an eccentric 3.9 day orbit around a massive O6.5V star. Observations at energies above 0.1 TeV (1011 eV) by the High Energy Stereoscopic System (HESS) in 2004 revealed that LS 5039 is a source of Very High Energy (VHE) -rays and hence, is able to accelerate particles to multi-TeV energies. Deeper observations by HESS were carried out in 2005 in an effort to probe further the high energy astrophysics taking place. In particular, we have searched for orbital modulation of the VHE -ray flux, which if detected, would yield new information about the complex variation in -ray absorption and production within X-ray binary systems.&#13;\\nMethods. Observations at energies above 0.1 TeV (1011 eV), were carried out with the High Energy Stereoscopic System (HESS) of Cherenkov Telescopes in 2005. A timing analysis was performed on the dataset employing the Lomb-Scargle and Normalised Rayleigh statistics, and orbital phase-resolved energy spectra were obtained.&#13;\\nResults. The timing analysis reveals a highly significant (post-trial chance probability &lt;10-15) peak in the TeV emission periodogram at a frequency matching that of the 3.9 day orbital motion of the compact object around the massive stellar companion. This is the first time in -ray astronomy that orbital modulation has been observed, and periodicity clearly established using ground-based -ray detectors. The -ray emission is largely confined to half of the orbit, peaking around the inferior conjunction epoch of the compact object. Around this epoch, there is also a hardening of the energy spectrum in the energy range between 0.2 TeV and a few TeV.&#13;\\nConclusions. The -ray flux vs. orbital phase profile suggests the presence of -ray absorption via pair production, which would imply that a large fraction of the -ray production region is situated within ~1 AU of the compact object. This source size constraint can be compared to the collimated outflows or jets observed in LS 5039 resolved down to scales of a few AU. The spectral hardening is however not explained exclusively by the absorption effect, indicating that other effects are present, perhaps related to the -ray production mechanism(s). If the -ray emission arises from accelerated electrons, the hardening may arise from variations with phase in the maximum electron energies, the dominant radiative mechanism, and/or the angular dependence in the inverse-Compton scattering cross-section. Overall, these results provide new insights into the competing -ray absorption and production processes in X-ray binaries.