julilili42/papers huggingface dataset:
Synthesis of axially substituted gallium, indium and thallium phthalocyanines with nonlinear optical properties
2005-08-26

Axially substituted phthalocyanines with gallium, indium and thallium as central coordinated atoms have been synthesized for nonlinear optical (NLO) studies.In particular, the optical limiting effect of 2(3)-tetrabuylphthalocyaninato indium chloride (1), hexadecachlorophthalocyaninato indium chloride (2), 2,3-octa-(2-ethyl-hexyloxy) phthalocyaninato gallium chloride (3a), 2,3-octa-(2-ethyl-hexyloxy)phthalocyaninato indium chloride (3b), 2,3-octa-(2-ethylhexyloxy)phthalocyaninato indium trifluoroacetate (4a), 2,3-octa-(2-ethyl-hexyloxy)phthalocyaninato thallium trifluoroacetate (4b), and 2,3,9,10,16,17-hexa-(2-ethyl-hexyloxy) monobenzophthalocyaninato indium chloride (5) has been evaluated and compared when the NLO regime was determined by nanosecond laser pulses in the visible spectrum.In the case of complexes 1 and 4a the determination of the excited state absorption cross section at 532 nm could be possible due the verification of reversible saturation of NLO absorption in the adopted experimental conditions.This allowed the use of the steady-state solutions for the kinetic equations describing sequential multiphoton absorption.
Trajectory synthesis by hierarchical spatio-temporal correspondence
2005-08-26

We present several methods for the generation of complex human motion trajectories by linear combination of prototypical example trajectories with well-defined styles. These methods decompose longer trajectories automatically into movement primitives by robust matching with stored templates. To synthesize movement primitives with new style properties, segments from the prototype trajectories are linearly combined. These linear combinations are based on the computation of spatio-temporal correspondence between trajectory segments. The synthesized new movement primitives are automatically concatenated into longer action sequences, trying to minimize artifacts at the transition points. The proposed methods are evaluated by synthesizing movement sequences from martial arts ("karate katas") that include movements primitives with different styles. For assessing the physical correctness of the generated movements we employ a zero-moment-point criterion. This physical measure was very similar for real human movement trajectories and trajectories synthesized by linear combination. In addition, we evaluated the perceptual quality of the synthesized movement sequences in a psychophysical study, involving naive subjects and computer graphics experts. We found significant differences between the different methods. For complex movements methods based on space-time correspondence seem to outperform algorithms without time-warping. In addition, computer graphics experts seem to be more sensitive to artifacts in the trajectories than normal observers.
Real-time decompression and visualization of animated volume data
2005-08-29

Interactive exploration of animated volume data is required by many application, but the huge amount of computational time and storage space needed for rendering does not yet allow the visualization of animated volumes. In this paper, we introduce an algorithm running at interactive frame rates using 3D wavelet transforms that allows for any wavelet, motion compensation techniques and various encoding schemes of the resulting wavelet coefficients to be used. We analyze different families and orders of wavelets for compression ratio and the introduced error. We use a quantization that has been optimized for the visual impression of the reconstructed volume, independent of the viewing algorithm. This enables us to achieve very high compression ratios while still being able to reconstruct the volume with as few visual artifacts as possible. A further improvement of the compression ratio has been achieved by applying a motion compensation scheme to exploit temporal coherency. Using these schemes, we are able to decompress each volume of our animation at interactive frame rates, while visualizing these decompressed volumes on a single PC. We also present a number of improved visualization algorithms for high-quality display using OpenGL hardware running at interactive frame rates on a standard PC.
Die Schichtstruktur von Cyamelurchlorid C6N7Cl3
2005-08-29

Abstract The Layer Structure of Cyameluric Chloride C 6 N 7 Cl 3 A solid state reaction of cyanuric chloride (trichloro‐ s ‐triazine C 3 N 3 Cl 3 ) with sodium dicyanamide (NaN(CN) 2 ) yielded some yellow, plate‐like crystals of cyameluric chloride (trichloro‐ s ‐heptazine C 6 N 7 Cl 3 ). The crystal structure was determined by single crystal X‐ray diffraction at 220 K and was solved in the monoclinic space group C 2/ c (no. 15) with Z = 24, a = 2319.4(4) pm, b = 1348.8(1) pm, c = 2063.4(3) pm, β = 118.38(2)° and V = 5.680(1) nm 3 . In the structure, the molecules of C 6 N 7 Cl 3 are forming layers parallel to the ab‐plane, which are separated from each other by a gap of approximately 300 pm. In each of these layers, the molecules seem to be arranged around pseudo‐threefold axes, showing an almost trigonal structure pattern.
Connectivity shapes
2005-08-29

We describe a method to visualize the connectivity graph of a mesh using a natural embedding in 3D space. This uses a 3D shape representation that is based solely on mesh connectivity: the connectivity shape. Given a connectivity, we define its natural geometry as a smooth embedding in space with uniform edge lengths and describe efficient techniques to compute it. Our main contribution is to demonstrate that a surprising amount of geometric information is implicit in the connectivity. We also show how to generate connectivity shapes that approximate given 3D shapes. Potential applications of connectivity shapes to modeling and mesh coding are described.
The MultiSite Spectroscopic Telescope campaign: 2 m spectroscopy of the V361 Hya variable PG 1605+072
2005-08-29

We present results and analysis for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST)&#13;\\ncampaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG1605+072&#13;\\nsimultaneously in velocity and photometry and to resolve as many of the &gt;50 known modes as possible, which will allow a&#13;\\ndetailed asteroseismological analysis. We have obtained over 150 h of spectroscopy, leading to an unprecedented noise level&#13;\\nof only 207 m s−1. We report here the detection of 20 frequencies in velocity, with two more likely just below our detection&#13;\\nthreshold. In particular, we detect 6 linear combinations, making PG1605+072 only the second star known to show such&#13;\\nfrequencies in velocity. We investigate the phases of these combinations and their parent modes and find relationships between&#13;\\nthem that cannot be easily understood based on current theory. These observations, when combined with our simultaneous&#13;\\nphotometry, should allow asteroseismology of this most complicated of sdB pulsators.
Distributed high performance computing in heterogeneous environments with DOTS
2005-08-29

This paper deals with high performance computing in heterogeneous clusters using the Distributed Object-Oriented Threads System (DOTS). DOTS is a parallelization platform that enables the programmer to build distributed parallel applications using a high level and easy-to-use parallel programming paradigm. It integrates a wide range of different systems (from realtime kernels to mainframes) into a single system environment for high performancecomputing. A special design focus of DOTS is to optimize usability aspects.Additionally, the paper discusses three advanced features of DOTS that especially support its deployment in heterogeneous environments for high performance computing.For defining the parallel environment and for documenting and evaluating the results of program runs an integrated XML centric approach is presented. A light-weight checkpointingmechanism which is seamlessly integrated into DOTS and especially designed for heterogeneous environments is described. DOTS is based on a highly customizablecommunication kernel. Run time measurements are presented that prove the efficiency of the communication kernel in heterogeneous clusters. Also, performance measurements of a non-trivial parallel application from the field of Symbolic Computation are presented, which revealed good speedups on a heterogeneous cluster of workstations.
Dynamical behavior of mutually coupled semiconductor lasers: experimental investigations
2005-08-29

Summary form only given. The study of dynamical coupling phenomena of semiconductor lasers is of great current interest and leads to new insights into the fundamental phenomena of synchronization effects and is indispensable for the realization of coherently coupled lasers. In this work, we experimentally study the dynamical behavior of two mutually coupled semiconductor lasers under moderate to strong coupling conditions. Depending on the injection current and the temperature, determining the relative frequency detuning, we have investigated the emission dynamics of both lasers. The experiments have been performed using two similar Fabry-Perot lasers placed at a distance of /spl sim/1.4 m. We have detected the intensity by a fast photodiode and analyzed it by a fast digitizing oscilloscope with 3 GHz bandwidth and an electrical spectrum analyzer. Furthermore, optical spectra with a resolution of 0.1 nm have been measured. We find chaotic low frequency fluctuations in the dynamical behavior of both lasers, exhibiting the similar features like those obtained for delayed moderate optical feedback. The dropouts of the intensity and the sub ns oscillations are identical in both lasers, but delayed to each other where the delay is /spl sim/10 ns, given by twice the propagation time between the lasers. An example of the synchronized intensity dynamics of the two lasers is depicted.
Unambiguous detection of astaxanthin and astaxanthin fatty acid esters in krill (Euphausia superba Dana)
2005-08-30

Abstract HPLC atmospheric pressure chemical ionization (APCI)/MS, GC MS, HPLC diode array detection (DAD), and NMR were used for the identification of astaxanthin and astaxanthin fatty acid esters in krill ( Euphausia superba Dana ). Matrix solid phase dispersion was applied for the extraction of the carotenoids. This gentle and expeditious extraction technique for solid and viscous samples leads to distinct higher enrichment rates than the conventional liquid–liquid extraction. The chromatographic separation was achieved employing a C 30 RP column that allows the separation of shape‐constrained geometrical isomers. A methanol/ tert ‐butylmethyl ether/water gradient was applied. ( all ‐E) Astaxanthin and the geometrical isomers were identified by HPLC APCI/MS, by coelution with isomerized authentical standard, by UV spectroscopy (DAD), and three isomers were unambiguously assigned by microcoil NMR spectroscopy. In this method, microcoils are transversally aligned to the magnetic field and have an increased sensitivity compared to the conventional double‐saddle Helmholtz coils, thus enabling the measurement on small samples. The carotenol fatty acid esters were saponified enzymatically with Lipase type VII from Candida rugosa . The fatty acids were detected by GC MS after transesterification, but also without previous derivatization by HPLC APCI/MS. C14:0, C16:0, C16:1, C18:1, C20:0, C20:5, and C22:6 were found in astaxanthin monoesters and in astaxanthin diesters. ( all ‐E) Astaxanthin was identified as the main isomer in six fatty acid ester fractions by NMR. Quantitation was carried out by the method of internal standard. (13‐ cis ) Astaxanthin (70 μg/g), 542 μg/g ( all ‐E) astaxanthin, 36 μg/g unidentified astaxanthin isomer, 62 μg/g (9‐ cis ) astaxanthin, and 7842 μg/g astaxanthin fatty acid esters were found.
The Phosphorylation of Ser318 of Insulin Receptor Substrate 1 Is Not per se Inhibitory in Skeletal Muscle Cells but Is Necessary to Trigger the Attenuation of the Insulin-stimulated Signal
2005-08-30

The Ser/Thr phosphorylation of insulin receptor substrate 1 (IRS) is one key mechanism to stimulate and/or attenuate insulin signal transduction. Using a phospho-specific polyclonal antibody directed against phosphorylated Ser(318) of IRS-1, we found a rapid and transient insulin-stimulated phosphorylation of Ser(318) in human and rodent skeletal muscle cell models and in muscle tissue of insulin-treated mice. None of the investigated insulin resistance-associated factors (e.g. high glucose, tumor necrosis factor-alpha, adrenaline) stimulated the phosphorylation of Ser(318). Studying the function of this phosphorylation, we found that replacing Ser(318) by alanine completely prevented both the attenuation of insulin-stimulated Akt/protein kinase B Ser(473) phosphorylation and glucose uptake after 60 min of insulin stimulation. Unexpectedly, after acute insulin stimulation, we observed that phosphorylation of Ser(318) is not inhibitory but rather enhances insulin signal transduction because introduction of Ala(318) led to a reduction of the insulin-stimulated Akt/protein kinase B phosphorylation. Furthermore, replacing Ser(318) by glutamate, i.e. mimicking phosphorylation, improved glucose uptake after acute insulin stimulation. These data suggest that phosphorylation of Ser(318) is not per se inhibitory but is necessary to trigger the attenuation of the insulin-stimulated signal in skeletal muscle cells. Investigating the molecular mechanism of insulin-stimulated Ser(318) phosphorylation, we found that phosphatidylinositol 3-kinase-mediated activation of atypical protein kinase C-zeta and recruitment of protein kinase C-zeta to IRS-1 was responsible for this phosphorylation. We conclude that Ser(318) phosphorylation of IRS-1 is an early physiological event in insulin-stimulated signal transduction, which attenuates the continuing action of insulin.
High frequencies of functionally impaired cytokeratin 18‐specific CD8+ T cells in healthy HLA‐A2+ donors
2005-08-30

Abstract Combining cell surface phenotyping with functional analysis, human CD8 + T cells have been divided into several subsets which are being studied extensively in diverse physiological situations, such as viral infection, cancer and ageing. In particular, so‐called terminally differentiated effector cells possess a CD45RA + CCR7 – CD27 – CD28 – phenotype, contain perforin and, in different models, have been shown to exert direct ex vivo killing and to release interleukins upon both antigen‐nonspecific and ‐specific stimulation. Using HLA class I multimers, we have identified a high frequency of peripheral CD8 + T cells that recognize a peptide derived from the self protein cytokeratin 18 presented by the HLA‐A*0201 molecule. These cells can be detected in approximately 15% of the HLA‐A2‐positive healthy donors tested. A detailed analysis revealed that they must have divided extensively in vivo , have an effector cell phenotype and express various natural killer cell‐associated receptors. Interestingly, however, they remained unresponsive to antigen‐specific stimulation in vitro in terms of cytotoxicity and cytokine secretion. Thus, cytokeratin 18‐specific cells constitute a frequently encountered, new CD8 + T lymphocyte subpopulation without classical effector status and with so far unknown function.
Influence of clindamycin on the stability ofcoaandfnbBtranscripts and adherence properties ofStaphylococcus aureusNewman
2005-08-30

We investigated whether a subinhibitory concentration of clindamycin (Cli), corresponding to 1/2 the strain-specific minimum inhibitory concentration (MIC), could affect expression and stability of transcripts from genes coding for specific adhesins such as fibronectin binding proteins A (fnbA) and B (fnbB) as well as coagulase (coa) in Staphylococcus aureus strain Newman. Furthermore, the effect of 1/2 MIC of Cli on adherence properties and expression of type 5 capsular polysaccharides (CP5) was investigated. Northern slot blot experiments confirmed that the amount of coa- and fnbB-specific mRNA, in contrast to that of fnbA-specific mRNA, was increased 2-fold after treatment of S. aureus Newman with 1/2 MIC of Cli. Analysis of RNA stability revealed that the increased amounts of transcripts of coa and fnbB were due to stabilization of the respective mRNAs. However, when treated with 1/2 MIC of Cli, S. aureus Newman showed no significant changes neither in its adherence patterns to fibrinogen- or fibronectin-coated micotitre plates, nor to epithelial HEp-2 cells and also not in its CP5 expression. Therefore, we conclude that increased mRNA stability of fnbB and coa by 1/2 MIC Cli, in contrast to the situation seen with the protein biosynthesis inhibiting antibiotic florfenicol, does not result in an increase in adherence of S. aureus Newman.
Gene Expression Changes in Leukocytes During Cardiopulmonary Bypass Are Dependent on Circuit Coating
2005-08-30

Background— Cardiopulmonary bypass (CPB) results in a systemic inflammatory response. Leukocytes play a crucial role in inflammatory reactions. Their gene expression profile in the context of CPB is unknown. Methods and Results— In a prospective, randomized, and double-blind clinical trial, 12 male patients underwent elective coronary artery bypass grafting with either heparin-coated (group H) or protein-coated (group P) CPB circuits. Oligonucleotide microarray analyses of 22 283 genes were performed on circulating leukocytes, collected immediately before surgery and 6 hours after CPB. Microarray results were validated with real-time polymerase chain reaction. All patients had uneventful surgery, and no significant differences between groups were observed during the clinical course. Multiple statistical analyses with different methods were performed. Compared with preoperative expression at a threshold value of P &lt;0.01, postoperative expression revealed 814 upregulated and 1187 downregulated genes in group H compared with 99 upregulated and 231 downregulated in group P ( P &lt;0.001). Fifty genes exhibited a &gt;4-fold increase and 27 exhibited a &gt;4-fold decrease in group H, whereas only 7 genes exhibited upregulation and 7 revealed downregulation in group P. Microarray-pathway-profile-finder analyses determined 1405 upregulated and 1454 downregulated pathways in group H compared with 552 upregulated and 818 downregulated pathways in group P ( P &lt;0.01). Pathways related to inflammatory response exhibited highest z scores in group H, reflecting cellular inflammatory activation. Conclusions— Heparin coating resulted in a more profound alteration in leukocyte gene expression when compared with protein coating. Microarray analyses present an innovative approach for the evaluation and understanding of inflammatory reactions associated with CPB.
Sequential sensing with biosonar for natural landmark classification
2005-08-30

Echolocating bats can make nocturnal flights in acoustically cluttered environments with the use of echolocation. Their ability to evaluate targets in complete darkness provides mobile robots an opportunity to learn target detection, classification and identification with similar biomimetic platforms. In this work, natural landmark classification with a binaural system, a sequential sensing strategy and a frequency after reconstruction algorithm were developed and tested. The aim of the work is to overcome some inherent shortcomings of airborne sonar and take advantage of bats' perceived properties for mobile robots' navigation in natural environments. Experimental results suggest considerable improvements in classification accuracy can be achieved by the use of this sequential classification method.
The high‐affinity poplar ammonium importer PttAMT1.2 and its role in ectomycorrhizal symbiosis
2005-08-31

One way to elucidate whether ammonium could act as a nitrogen (N) source delivered by the fungus in ectomycorrhizal symbiosis is to investigate plant ammonium importers. Expression analysis of a high-affinity ammonium importer from Populus tremulax tremuloides (PttAMT1.2) and of known members of the AMT1 gene family from Populus trichocarpa was performed. In addition, PttAMT1.2 function was studied in detail by heterologous expression in yeast. PttAMT1.2 expression proved to be root-specific, affected by N nutrition, and strongly increased in a N-independent manner upon ectomycorrhiza formation. The corresponding protein had a K(M) value for ammonium of c. 52 microm. From the seven members of the AMT1 gene family, one gene was exclusively expressed in roots while four genes were detectable in all poplar organs but with varying degrees of expression. Ectomycorrhiza formation resulted in a strong upregulation of three of these genes. Our results indicate an increased ammonium uptake capacity of mycorrhized poplar roots and suggest, together with the expression of putative ammonium exporter genes in the ectomycorrhizal fungus Amanita muscaria, that ammonium could be a major N source delivered from the fungus towards the plant in symbiosis.
Blood-brain barrier invasion by group B Streptococcus depends upon proper cell-surface anchoring of lipoteichoic acid
2005-09-01

Group B streptococci (GBSs) are the leading cause of neonatal meningitis. GBSs enter the CNS by penetrating the blood-brain barrier (BBB), which consists of specialized human brain microvascular endothelial cells (hBMECs). To identify GBS factors required for BBB penetration, we generated random mutant libraries of a virulent strain and screened for loss of hBMEC invasion in vitro. Two independent hypo-invasive mutants possessed disruptions in the same gene, invasion associated gene (iagA), which encodes a glycosyltransferase homolog. Allelic replacement of iagA in the GBS chromosome produced a 4-fold decrease in hBMEC invasiveness. Mice challenged with the GBS DeltaiagA mutant developed bacteremia comparably to WT mice, yet mortality was significantly lower (20% vs. 90%), as was the incidence of meningitis. The glycolipid diglucosyldiacylglycerol, a cell membrane anchor for lipoteichoic acid (LTA) and predicted product of the IagA glycosyltransferase, was absent in the DeltaiagA mutant, which consequently shed LTA into the media. Attenuation of virulence of the DeltaiagA mutant was found to be independent of TLR2-mediated signaling, but bacterial supernatants from the DeltaiagA mutant containing released LTA inhibited hBMEC invasion by WT GBS. Our data suggest that LTA expression on the GBS surface plays a role in bacterial interaction with BBB endothelium and the pathogenesis of neonatal meningitis.