julilili42/papers huggingface dataset:
Depressed Natural Killer Cell Cytotoxicity againstPlasmodium falciparum–Infected Erythrocytes during First Pregnancies
2004-01-19

We measured natural killer (NK) cell cytotoxicity and cortisol and prolactin concentrations in peripheral venous blood samples obtained from pregnant Gabonese women at the time of delivery. The NK cell-mediated cytotoxicity against Plasmodium falciparum-infected erythrocytes in vitro was lower in samples obtained from primiparous women than in samples obtained from multiparous women; cortisol concentrations were significantly higher in primiparous women than in multiparous women, and prolactin concentrations were significantly lower. The highest cortisol concentrations were found in the plasma of P. falciparum-infected primiparous women. A positive correlation was found between cortisol concentration and parasite load; an inverse correlation was found between the magnitude of the NK cell cytolytic effect and cortisol production. A positive correlation was found between this effect and prolactin production. Thus, depressed NK cell cytotoxicity against P. falciparum-infected erythrocytes is correlated with high cortisol concentrations and may contribute to increased susceptibility to malaria during pregnancy.
Multiproxy approach to understanding the origin of Cretaceous pelagic limestone–marl alternations (DSDP site 391, Blake‐Bahama Basin)
2004-01-19

Abstract Limestone–marl alternations are usually directly interpreted to reflect cyclic palaeoenvironmental signals. However, uncertainty in such interpretations stems from the differential diagenesis that most limestone–marl alternations have undergone. Differential diagenesis results in markedly different alterations between limestones and marls and in the loss of comparability of many measurable parameters. For an unequivocal interpretation of the origin of rhythmic alternations, diagenetically robust parameters or parameters that clearly indicate the degree of diagenetic bias are required. The present study uses a multiproxy approach (independent biotic, sedimentary and geochemical parameters) in order to unravel the palaeoenvironmental signal recorded in Valanginian (Early Cretaceous) limestone–marl alternations from the Blake‐Bahama Basin (DSDP site 391). Using this approach, terrestrial and marine influences can be distinguished, changes in nutrient levels estimated and prediagenetic differences in the non‐carbonate fraction constrained. Surprisingly, no systematic variations in any of these parameters were observed between limestone and marl layers, implying that none of these was directly responsible for the formation of the rhythmic alternation. Hence, none of the current models of sedimentary formation of limestone–marl rhythmites is applicable here. Calcareous nannofossils are equally well preserved in limestone and marl layers, ruling out their dissolution in marl layers as a source of the calcite cement in the limestone beds. Sr values of 700–900 p.p.m. indicate that aragonite may have been present in the original, pelagic sediment. The assumption of fine‐grained sedimentary aragonite imported from nearby carbonate platforms as the source of the cement would explain a number of otherwise enigmatic features in these rhythmites, including the source of the calcite cement observed in the limestones, the equally good preservation of calcareous nannofossils in limestones and marls and the higher concentration of calcareous nannofossils in marl layers. The study demonstrates that examination of diagenetically inert parameters or parameters in which diagenetic effects can be filtered can yield unexpected results. Clearly, careful analysis of such parameters needs to be undertaken in order to make reliable palaeoenvironmental interpretations from rhythmite successions.
Synthesis and Some Properties of Aryl‐ and Aryloxy‐Substituted Phthalocyanines and Their Metal Complexes: A Comparison with Porphyrazine and Naphthalocyanine Analogues
2004-01-19

Abstract The preparation of new octakis[ m‐ (trifluoromethyl)phenyl]‐ and octakis[ m ‐(trifluoromethyl)phenoxy]phthalocyanines ( 6a and 6b ) and their complexes with magnesium ( 5a , 5b ) and indium ( 7a , 7b ) is described. Their spectroscopic properties and solubilities are discussed in relation to those of metal‐free and metallated octakis[ m ‐(trifluoromethyl)phenyl]porphyrazine, as well as those of metal m ‐(trifluoromethyl)phenyl‐ and m ‐(trifluoromethyl)phenoxy‐substituted 2,3‐naphthalocyanines. A drastic decrease in the solubilities of the metal‐free phthalocyanines in CH 2 Cl 2 was observed on comparing them with m ‐CF 3 ‐phenyl‐substituted porphyrazine. However, their solubilities in THF were high enough for NMR spectra to be recorded. Insertion of (chloro)indium into the cavities of these phthalocyanines noticeably enhances the solubilization of the macrocycles, including in CH 2 Cl 2 . (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2004)
Structured belief bases
2004-01-19

In this paper we discuss a formal approach to belief representation which stores proof-theoretic information together with formulae. It is illustrated how this additional information can be used in the context of belief revision. The general aims of this paper are the following three: First, we would like to give a descriptive approach to belief revision, in contrast to a normative one. Secondly, the given theory should avoid (the consequences of) logical omniscience of beliefs. Finally, from a broader point of view, the presented approach can be considered as a case study within the programme of proof-theoretic semantics. In this programme, the question is raised whether and how proof-theoretic information can be used as a basis for semantics.
Molecular dissection of water and glycerol permeability of the aquaglyceroporin from Plasmodium falciparum by mutational analysis
2004-01-20

The selectivity of aquaporins for water and solutes is determined by pore diameter. Paradoxically, the wider pores of glycerol facilitators restrict water passage by an unknown mechanism. Earlier we characterized an aquaglyceroporin from Plasmodium falciparum with high permeability for both glycerol and water. We use point mutations to demonstrate that amino acids directly lining the pore are not responsible for the excellent water permeability of the Plasmodium aquaglyceroporin but affect permeability of pentitols. Within a conserved WET triad in the extracellular C-loop we identified a Plasmodium aquaglyceroporin-specific glutamate (E125) located in proximity to a conserved arginine (R196) at the pore mouth. Mutation of E125 to serine largely abolished water permeability. Concomitantly, the activation energy for water permeation was increased by 4 kcal/mol. Mutation of the adjacent tryptophan to cysteine led to irreversible inhibition of water passage by Hg 2+ . This unequivocally proves the proximity of the couple W124/E125 close to the pore mouth. We conclude that in the Plasmodium aquaglyceroporin the electrostatic environment at the extracellular pore entry regulates water permeability.
The Influence of Pulse and Respiration on Spinal Cerebrospinal Fluid Pulsation
2004-01-20

The pulsation in the lower spine seems to be related to a second motor of CSF movement because there is a rising respiratory influence and a reappearance of pulsation waves. Physiological spinal CSF pulsation contains a relevant respiratory component.
TheSp8zinc-finger transcription factor is involved in allometric growth of the limbs in the beetle Tribolium castaneum
2004-01-20

Members of the Sp gene family are involved in a variety of developmental processes in both vertebrates and invertebrates. We identified the ortholog of the Drosophila Sp-1 gene in the red flour beetle Tribolium castaneum, termed T-Sp8 because of its close phylogenetic relationship to the vertebrate Sp8 genes. During early embryogenesis, T-Sp8 is seen in segmental stripes. During later stages, TSp8 is dynamically expressed in the limb buds of the Tribolium embryo. At the beginning of bud formation, TSp8 is uniformly expressed in all body appendages. As the limbs elongate, a ring pattern develops sequentially and the expression profile at the end of embryogenesis correlates with the final length of the appendage. In limbs that do not grow out like the labrum and the labium, T-Sp8 expression remains uniform, whereas a two-ring pattern develops in the longer antennae and the maxillae. In the legs that elongate even further, four rings of T-Sp8 expression can be seen at the end of leg development. The role of T-Sp8 for appendage development was tested using RNAi. Upon injection of double stranded T-Sp8 RNA, larvae develop with dwarfed appendages. Affected T-Sp8RNAi legs were tested for the presence of medial and distal positional values using the expression marker genes dachshund and Distal-less, respectively. The results show that a dwarfed TSp8RNAi leg consists of proximal,medial and distal parts and argues against T-Sp8 being a leg gap gene. Based on the differential expression pattern of T-Sp8 in the appendages of the head and the thorax and the RNAi phenotype, we hypothesise that T-Sp8 is involved in the regulation of limb-length in relation to body size - a process called allometric growth.
Chronic renal denervation prevents glomerular hyperfiltration in diabetic rats
2004-01-21

Renal nerves appear to be significantly involved in the mediation of glomerular hyperfiltration in experimental DM. If the kidney is prevented from sympathetic nerve stimulation, structural changes due to early diabetic nephropathy, i.e. glomerular enlargement, are abolished.
The properties of the three-nucleon system with the dressed-bag model forNNinteraction: I. New scalar three-body force
2004-01-21

A multi-component formalism is developed to describe three-body systems with nonstatic pairwise interactions and non-nucleonic degrees of freedom. The dressed-bag model for interaction based on the formation of an intermediate six-quark bag dressed by a -field is applied to the system, where it results in a new three-body force between the six-quark bag and a third nucleon. Concise variational calculations of bound states are carried out in the dressed-bag model including the new three-body force. It is shown that this three-body force gives at least half the total binding energy, while the weight of non-nucleonic components in the H and He wavefunctions can exceed 10%. The new force model provides a very good description of bound states with a reasonable magnitude of the coupling constant. The model can serve as a natural bridge between dynamical description of few-nucleon systems and the very successful Walecka approach to heavy nuclei and nuclear matter.
Clinicopathological findings of choroidal neovascularisation following verteporfin photodynamic therapy
2004-01-21

PDT did not cause a thrombosis of the vessels within the CNV three days after PDT. Severe endothelial damage of the CNV was observed and is likely a primary effect of PDT. Non-perfusion of the CNV at this stage is possibly secondary to occlusion at a deeper level, namely the underlying feeding choroid.
The properties of the three-nucleon system within the dressed bag model for 2Nand 3Nforces: II. Coulomb and CSB effects
2004-01-21

Coulomb and charge-symmetry breaking effects in the He ground state\\nwithin the dressed dibaryon model developed recently for and forces\\nare examined in detail. Particular attention has been paid to the Coulomb\\ndisplacement energy and rms charge\\nradii of H and He. A new scalar force between the third nucleon a ^3 \\\\Delta\\nE_C$ obtained here, the role of the effects of charge symmetry breaking in the\\nnuclear force is discussed.\\n
An age‐dependent population equation with delayed birth process
2004-01-22

Abstract Within a semigroup framework, we discuss well posedness and qualitative behaviour of an age‐dependent population equation with delay in the birth process. Using positivity and Perron–Frobenius theory we obtain an explicit stability criterion. Copyright © 2004 John Wiley &amp; Sons, Ltd.
Spiking of Contemporary Human Template DNA with Ancient DNA Extracts Induces Mutations Under PCR and Generates Nonauthentic Mitochondrial Sequences
2004-01-22

Proof of authenticity is the greatest challenge in palaeogenetic research, and many safeguards have become standard routine in laboratories specialized on ancient DNA research. Here we describe an as-yet unknown source of artifacts that will require special attention in the future. We show that ancient DNA extracts on their own can have an inhibitory and mutagenic effect under PCR. We have spiked PCR reactions including known human test DNA with 14 selected ancient DNA extracts from human and nonhuman sources. We find that the ancient DNA extracts inhibit the amplification of large fragments to different degrees, suggesting that the usual control against contaminations, i.e., the absence of long amplifiable fragments, is not sufficient. But even more important, we find that the extracts induce mutations in a nonrandom fashion. We have amplified a 148-bp stretch of the mitochondrial HVRI from contemporary human template DNA in spiked PCR reactions. Subsequent analysis of 547 sequences from cloned amplicons revealed that the vast majority (76.97%) differed from the correct sequence by single nucleotide substitutions and/or indels. In total, 34 positions of a 103-bp alignment are affected, and most mutations occur repeatedly in independent PCR amplifications. Several of the induced mutations occur at positions that have previously been detected in studies of ancient hominid sequences, including the Neandertal sequences. Our data imply that PCR-induced mutations are likely to be an intrinsic and general problem of PCR amplifications of ancient templates. Therefore, ancient DNA sequences should be considered with caution, at least as long as the molecular basis for the extract-induced mutations is not understood.
Viscosity of Fluids in Subduction Zones
2004-01-23

The viscosities of aqueous fluids with 10 to 80 weight percent dissolved silicates have been measured at 600° to 950°C and 1.0 to 2.0 gigapascals by in situ observation of falling spheres in the diamond anvil cell. The viscosities at 800°C range from 10 –4 to 10 0.5 pascal seconds. The combination of low viscosities with a favorable wetting angle makes silicate-rich fluid an efficient agent for material transport at low-volume fractions. Our results therefore suggest that there may be a direct relationship between the position of the volcanic front and the onset of complete miscibility between water and silicate melt in the subducting slab.
The Thought Translation Device: structure of a multimodal brain-computer communication system
2004-01-23

The Thought Translation Device (TTD) is a brain-computer-interface (BCI) which successfully enabled totally paralyzed patients to communicate by using their brain potentials only. An extended version of the TTD has been developed running on any MS-Windows PC and its architecture is described. A variety of filter modules (temporal and spectral filters, classifier, etc.) can be combined in a configurable order for online processing and feedback of physiological data. Statistical analysis methods are implemented for online and offline classification of SCP and spectral EEG data. As many patients suffering from Amyotrophic Lateral Sclerosis (ALS) in its final stage no longer have the ability to focus on a computer screen, the TTD is now able to present all information necessary for brain-computer communication by voice and sound as well as visually. The TTD is currently used for various studies with paralyzed and comatose patients, patients with epilepsy and children with attention deficit disorders.
Influence of Fermi surface topology on the quasiparticle spectrum in the vortex state
2004-01-23

We study the influence of Fermi surface topology on the quasiparticle density of states in the vortex state of type II superconductors. We observe that the field dependence and the shape of the momentum and spatially averaged density of states is affected significantly by the topology of the Fermi surface. We show that this behavior can be understood in terms of characteristic Fermi surface functions and that an important role is played by the number of points on the Fermi surface at which the Fermi velocity is directed parallel to the magnetic field. A critical comparison is made with a broadened BCS type density of states, that has been used frequently in analysis of tunneling data. We suggest a new formula as a replacement for the broadened BCS model for the special case of a cylindrical Fermi surface. We apply our results to the two gap superconductor MgB and show that in this particular case the field dependence of the partial densities of states of the two gaps behaves very differently due to the different topologies of the corresponding Fermi surfaces, in qualitative agreement with recent tunneling experiments.
A fast finite element solution for cloth modelling
2004-01-24

We present an efficient model based on finite elements for viscoelastic, highly flexible surfaces. It is particularly designed for numerically stiff materials such as textiles because it yields linear equations in each time step and allows fast time stepping in an implicit integration method. This is achieved by reducing the nonlinear elasticity problem to a planar, linear one in each step. We apply this model to a garment simulation in which we assemble garments from CAD cloth patterns, seam these together, and animate the cloth in dynamic scenes with any chosen material properties. This results in a physically accurate but also fast simulation.
A stereo electronic nose for a mobile inspection robot
2004-01-24

This paper describes the design of a gas-sensitive system that is suitable for use on a mobile robot ("mobile nose"). The stereo architecture comprises two equivalent sets of gas sensors mounted inside separated ventilated tubes (or "nostrils"). To characterise the dynamic response, the whole system is modelled as a first-order sensor. The corresponding parameters, including the response and recovery time, can be obtained by fitting this model to the values recorded during a simple experiment described in this paper. Our experiments confirmed the suitability of the applied model and permitted a quantitative comparison of different set-ups. It is shown that using suction fans lowers the recovery time of the metal oxide gas sensors by a factor of two, while a solid separation between the tubes (a "septum") is necessary to maintain the sensitivity of the mobile nose to concentration gradients.
Automated EEG feature selection for brain computer interfaces
2004-01-24

A brain computer interface (BCI) utilizes signals derived from electroencephalography (EEG) to establish a connection between a person's state of mind and a computer based signal processing system that interprets the EEG signals. The choice of suitable features of the available EEG signals is crucial for good BCI communication. The optimal set of features is strongly dependent on the subjects and on the used experimental paradigm. Based upon EEG data of an existing BCI system, we present a wrapper method for the automated selection of features. The proposed method combines a genetic algorithm (GA) for the selection of feature with a support vector machine (SVM) for their evaluation. Applying this GA-SVM method to data of several subjects and two different experimental paradigms, we show that our approach leads to enhanced or even optimal classification accuracy.
Differential Gene Expression in Auristatin PHE-Treated Cryptococcus neoformans
2004-01-24

ABSTRACT The antifungal pentapeptide auristatin PHE was recently shown to interfere with microtubule dynamics and nuclear and cellular division in the opportunistic pathogen Cryptococcus neoformans. To gain a broader understanding of the cellular response of C. neoformans to auristatin PHE, mRNA differential display (DD) and reverse transcriptase PCR (RT-PCR) were applied. Examination of approximately 60% of the cell transcriptome from cells treated with 1.5 times the MIC (7.89 μM) of auristatin PHE for 90 min revealed 29 transcript expression differences between control and drug-treated populations. Differential expression of seven of the transcripts was confirmed by RT-PCR, as was drug-dependent modulation of an additional seven transcripts by RT-PCR only. Among genes found to be differentially expressed were those encoding proteins involved in transport, cell cycle regulation, signal transduction, cell stress, DNA repair, nucleotide metabolism, and capsule production. For example, RHO1 and an open reading frame (ORF) encoding a protein with 91% similarity to the Schizophyllum commune 14-3-3 protein, both involved in cell cycle regulation, were down-regulated, as was the gene encoding the multidrug efflux pump Afr1p. An ORF encoding a protein with 57% identity to the heat shock protein HSP104 in Pleurotus sajor - caju was up-regulated. Also, three transcripts of unknown function were responsive to auristatin PHE, which may eventually contribute to the elucidation of the function of their gene products. Further study of these differentially expressed genes and expression of their corresponding proteins are warranted to evaluate how they may be involved in the mechanism of action of auristatin PHE. This information may also contribute to an explanation of the selectivity of auristatin PHE for C. neoformans . This is the first report of drug action using DD in C. neoformans.
An absolute positioning system for 100 euros
2004-01-24

This paper describes an absolute positioning system, which provides accurate and reliable measurements using low-cost equipment that is easy to set up. The system uses a number of fixed web-cameras to track a distinctly coloured object. In order to calculate the (x,y) position of this object, estimates calculated by triangulation from each combination of two cameras are combined, resulting in centimeter-level accuracy. Example applications, including tracking of mobile robots and persons, are described. An extended set-up is also introduced, which allows determination of the heading of a two coloured object from single images
FAIR true‐FISP perfusion imaging of the kidneys
2004-01-26

Abstract Most arterial spin labeling (ASL) techniques apply echoplanar imaging (EPI) because this strategy provides relatively high SNR in short measuring times. Unfortunately, those techniques are very susceptible to static magnetic field inhomogeneities and perfusion signals from organs with fast transverse relaxation might decrease due to the exchange of water molecules in capillaries and organ tissue combined with relatively long echo times of EPI sequences. To overcome these problems a novel imaging technique, FAIR True‐FISP, was developed. It combines a FAIR (flow‐sensitive alternating inversion recovery) perfusion preparation and a true fast imaging with steady precession (True‐FISP) data acquisition strategy. True‐FISP was chosen since this sequence type does not show the mentioned disadvantages of EPI, but provides a similar SNR per measuring time. An important problem of this approach is that True‐FISP sequences usually work in a steady state which is independent of a previous preparation of magnetization. For this reason a sequence structure had to be developed which keeps the advantages of True‐FISP and makes the signal intensity sensitive to the FAIR preparation. Breathhold and nonbreathhold examinations of kidneys are presented and possible strategies to quantitative flow measurements are reported. It is shown that correction of spatially inhomogeneous receiver coil characteristics is easily feasible and leads to clinically valuable perfusion examinations of kidneys without application of potentially nephrotoxic contrast media. Magn Reson Med 51:353–361, 2004. © 2004 Wiley‐Liss, Inc.