julilili42/papers huggingface dataset:
Synthesis and Solid-Phase Application of a 9-Xanthenyl Handle
2001-06-01

Abstract The acid-labile 5-[(9-aminoxanthen-2-yl)oxy]valeric acid was prepared in a six-step route. The usefulness of the resulting handle was investigated with solid-phase peptide synthesis of cholecystokinin-8 sulfate and the phosphorylated fragment of the ζ-subunit of the T-cell receptor complex 138-144.
Quality Planning for Minimally Invasive Procedures in Neurosurgery
2001-06-01

Parallel to the introduction of a minimally invasive method in a department, a documentation system should be introduced for quality management. The first step of quality management of an innovation is quality planning. During the course of patients being treated neuroendoscopically, the pre- and postoperative imaging, the intraoperative video recording, the patient-relevant files and the data of the planning have to be documented. These amounts of data require a multimedial documentation concept. We found the CD-ROM as an optimal documentation media because the discs are both cheap and easily accessible and once stored extremely robust against external influences. Therefore, every neuroendoscopically treated patient is documented with all relevant pictures, files and video sequences on a single CD-ROM.
Verifying the Kugo-Ojima Confinement Criterion in Landau Gauge Yang-Mills Theory
2001-06-04

Expanding the Landau gauge gluon and ghost two-point functions in a power series we investigate their infrared behavior. The corresponding powers are constrained through the ghost Dyson-Schwinger equation by exploiting multiplicative renormalizability. Without recourse to any specific truncation we demonstrate that the infrared powers of the gluon and ghost propagators are uniquely related to each other. Constraints for these powers are derived, and the resulting infrared enhancement of the ghost propagator signals that the Kugo-Ojima confinement criterion is fulfilled in Landau gauge Yang-Mills theory.
Low-frequency flux noise and visualization of vortices in a YBa2Cu3O7 dc superconducting quantum interference device washer with an integrated input coil
2001-06-04

We used low-temperature scanning electron microscopy (LTSEM) for imaging quantized magnetic flux (vortices) in dc superconducting quantum interference devices (SQUIDs) with approximately 1 μm spatial resolution at temperature T=77 K in a controllable magnetic field up to 20 μT. We demonstrate that LTSEM allows to image the spatial distribution of vortices in a YBa2Cu3O7/SrTiO3/YBa2Cu3O7 multilayer thin-film structure consisting of a dc SQUID washer with an integrated input coil on top. Simultaneously, we are able to measure the low-frequency noise of the sample under test, which allows to correlate the spatial distribution of vortices with low-frequency noise in the SQUID.
<title>Disease pattern recognition in FT-IR spectra of human sera</title>
2001-06-04

We observed differences between the mid-infrared spectra of sera originating from healthy volunteers and from patients with diabetes mellitus or rheumatoid arthritis. These differences were found to be significant in terms of the Fisher criterion, the t-test, and the Kolmogorov-Smirnov test. The significance allows for a classification of the spectra and a probability (`DPR-score') of belonging to the class `healthy' can be computed. In comparing the samples from 80 diabetes patients with samples from 40 healthy volunteers we are able to achieve a sensitivity and a specificity of 80% and above. The DPR-score correlates better with the actual status of health than the glucose concentration alone. In a study on rheumatoid arthritis we compared the spectral signatures of sera taken from 188 rheumatoid arthritis patients and sera from 196 healthy volunteers. By applying linear discriminant analysis to 2/3 of the samples we are able to classify the remaining third of the samples (independent validation) with a sensitivity of 84% and a specificity of 88%.
Antiferromagnetic phase in the Hubbard model by means of the composite operator method
2001-06-07

We have investigated the antiferromagnetic phase of the 2D, the 3D and the\\nextended Hubbard models on a bipartite cubic lattice by means of the Composite\\nOperator Method within a two-pole approximation. This approach yields a fully\\nself-consistent treatment of the antiferromagnetic state that respects the\\nsymmetry properties of both the model and the algebra. The complete phase\\ndiagram, as regards the antiferromagnetic and the paramagnetic phases, has been\\ndrawn. We firstly reported, within a pole approximation, three kinds of\\ntransitions at half-filling: Mott-Hubbard, Mott-Heisenberg and Heisenberg. We\\nhave also found a metal-insulator transition, driven by doping, within the\\nantiferromagnetic phase. This latter is restricted to a very small region near\\nhalf filling and has, in contrast to what has been found by similar approaches,\\na finite critical Coulomb interaction as lower bound at half filling. Finally,\\nit is worth noting that our antiferromagnetic gap has two independent\\ncomponents: one due to the antiferromagnetic correlations and another coming\\nfrom the Mott-Hubbard mechanism.\\n
Ethical, Biological and Legal Aspects in the use of Human Embryonic Stem Cells in Germany
2001-06-07

The first derivation and successful long-term cultivation of human embryonic stem (ES) cells and embryonic germ (EG) cells in November 1998 [1,2] was one of the most important scientific successes in recent years. Science Magazine ranked it as the breakthrough of the year in 1999 [3]. Indeed, because of their theoretical potential to differentiate in vitro into every possible type of cell in the body, human embryonic stem cells are considered to be very promising for many fields of medicine and biology. Researchers are especially interested in investigating their potential for transplantation medicine. But in most countries ethical and legal difficulties concerning the derivation and the use of human embryonic stem cells hinder research in this field.
Influence of Pressure upon Coupling Pressurized Capillary Electrochromatography with Nuclear Magnetic Resonance Spectroscopy
2001-06-12

In this work, the influence of supplementary pressure on the separation efficiency of pressurized capillary electrochromatography (pCEC) was examined. At low pressures of up to 30 bar, which is more than sufficient to prevent bubble formation, no significant loss in separation efficiency is observed. Even at 100 bar, the efficiency of pCEC is still significantly better than without application of an electric field. In addition, analysis times are drastically reduced compared to both capillary electrochromatography (CEC) and capillary HPLC. On the basis of these results, an improved interface for capillary NMR coupling is described and used for the separation and identification of a mixture of unsaturated fatty acid methyl esters. Under these conditions, the analysis time could be shortened by up to a factor of 10 when pCEC is coupled to NMR spectroscopy.
Neurotransmitter coding of enteric neurones in the submucous plexus is changed in non‐inflamed rectum of patients with Crohn’s disease
2001-06-15

Knowledge of the neurochemical coding of submucosal neurones in the human gut is important to assess neuronal changes under pathological conditions. We therefore investigated transmitter colocalization patterns in rectal submucosal neurones in normal tissue (n=11) and in noninflamed tissue of Crohn’s disease (CD) patients (n=17). Neurone‐specific enolase (NSE), choline acetyltransferase (ChAT), vasoactive intestinal polypeptide (VIP), substance P (SP), nitric oxide synthase (NOS) and calcitonin gene‐related peptide (CGRP) were detected immunohistochemically in whole‐mount preparations from rectal biopsies. The neuronal marker NSE revealed no differences in the number of cells per ganglion (controls 5.0; CD 5.1). Four cell populations with distinct neurochemical codes were identified. The sizes of the populations ChAT/VIP (58% vs. 55%), ChAT/SP (8% vs. 8%), and ChAT/– (22% vs. 22%) were similar in control and CD. The population VIP/– was significantly increased in CD (12% vs. 2% in controls). Unlike in controls, all NOS neurones colocalized ChAT in CD. Thickened CGRP‐fibres occurred in CD. We identified neurochemically distinct populations in the human submucous plexus. The increase in the VIP/– population, extensive colocalization of ChAT and NOS and hypertrophied CGRP fibres indicated adaptive changes in the enteric nervous system in noninflamed rectum of CD patients.
Short wavelength spectrum and Hamiltonian stability of vortex rings
2001-06-18

We compare dynamical and energetical stability criteria for vortex rings. It is argued that vortex rings will be intrinsically unstable against perturbations with short wavelengths below a critical wavelength because the canonical vortex Hamiltonian is unbounded from below for these modes. To explicitly demonstrate this behavior, we derive the oscillation spectrum of vortex rings in incompressible, inviscid fluids within a geometrical cutoff procedure for the core. The spectrum develops an anomalous branch of negative group velocity and approaches the zero of energy for wavelengths that are about six times the core diameter. We show the consequences of this dispersion relation for the thermodynamics of vortex rings in superfluid 4He at low temperatures.
Strange Quark Polarization of the Nucleon: A Parameter-Independent Prediction of the Chiral Potential Model
2001-06-18

We perform a one-loop calculation of the strange quark polarization (Deltas) of the nucleon in an SU(3) chiral potential model. We find that if the intermediate quark excited states are summed over in a proper way, i.e., summed up to a given energy instead of given radial and orbital quantum numbers, Deltas turns out to be almost independent of all the model parameters: quark masses and potential strengths. The contribution from the quark-antiquark pair creation and annihilation " Z" diagrams is found to be significant. Our numerical results agree quite reasonably with experiments and lattice QCD calculations.
ChemInform Abstract: An Expeditious Approach to Trisubstituted Chiral Thiazolines.
2001-06-19

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Recommendations for the ethical development and use of medical decision-support systems.
2001-06-20

Medical decision support systems (MDSS) play an increasingly important role in medical practice. By assisting physicians with making clinical decisions, MDSS are expected to improve the quality of medical care. However, there are also concerns that malfunctioning or inappropriate use of MDSS could jeopardize the well-being of the patient. While several authors have already discussed ethical issues arising with the use of computer-assisted medical decision making, there is still no consensus about the ethically appropriate use of MDSS. Based on a review and synthesis of previous relevant work, this paper proposes a comprehensive set of recommendations for the ethical development and application of MDSS.
Master-slave synchronization in chaotic discrete-time oscillators
2001-06-20

In this paper, we study a simple discrete-time neural oscillator model that, in certain parameter regimes, exhibits periodic or chaotic dynamics. The present model with intrinsically chaotic dynamics is capable of spatiotemporal information processing: in response to constant external stimulation, the oscillator can switch into different chaotic states restricted to distinct parts of the phase space. Of particular interest is the processing of time-dependent input in a master-slave configuration of two coupled oscillators. Here, the response of an oscillator is studied by driving it with the signal of the other. Following the input, the response system adapts to the state of the drive. For a chaotic drive, we can observe generalized synchronization. The onset of adaptation to the drive state by the response is accompanied by on-off intermittency resulting in irregular bursting behavior.
Glaucocystophytes
2001-06-20

Abstract The glaucocystophytes are a small group of photosynthetic, unicellular algae that possess cyanobacteria‐like plastids with prokaryotic peptidoglycans, coded in the cell nucleus; they are located on the base of the evolutionary tree towards higher plants.
Intracellular Anions as the Voltage Sensor of Prestin, the Outer Hair Cell Motor Protein
2001-06-22

Outer hair cells (OHCs) of the mammalian cochlea actively change their cell length in response to changes in membrane potential. This electromotility, thought to be the basis of cochlear amplification, is mediated by a voltage-sensitive motor molecule recently identified as the membrane protein prestin. Here, we show that voltage sensitivity is conferred to prestin by the intracellular anions chloride and bicarbonate. Removal of these anions abolished fast voltage-dependent motility, as well as the characteristic nonlinear charge movement (“gating currents”) driving the underlying structural rearrangements of the protein. The results support a model in which anions act as extrinsic voltage sensors, which bind to the prestin molecule and thus trigger the conformational changes required for motility of OHCs.
Discrete Cleavage Motifs of Constitutive and Immunoproteasomes Revealed by Quantitative Analysis of Cleavage Products
2001-06-25

Proteasomes are the main proteases responsible for cytosolic protein degradation and the production of major histocompatibility complex class I ligands. Incorporation of the interferon γ–inducible subunits low molecular weight protein (LMP)-2, LMP-7, and multicatalytic endopeptidase complex–like (MECL)-1 leads to the formation of immunoproteasomes which have been associated with more efficient class I antigen processing. Although differences in cleavage specificities of constitutive and immunoproteasomes have been observed frequently, cleavage motifs have not been described previously. We now report that cells expressing immunoproteasomes display a different peptide repertoire changing the overall cytotoxic T cell–specificity as indicated by the observation that LMP-7−/− mice react against cells of LMP-7 wild-type mice. Moreover, using the 436 amino acid protein enolase-1 as an unmodified model substrate in combination with a quantitative approach, we analyzed a large collection of peptides generated by either set of proteasomes. Inspection of the amino acids flanking proteasomal cleavage sites allowed the description of two different cleavage motifs. These motifs finally explain recent findings describing differential processing of epitopes by constitutive and immunoproteasomes and are important to the understanding of peripheral T cell tolerization/activation as well as for effective vaccine development.
Segregation of granular media by diffusion and convection
2001-06-27

A diffusion-convection equation is used to model granular segregation within a mixture of particles of different size, shape, or surface structure in a vertical vessel. Convection describes competition between species in vertical direction whereas random noise (shaking) allows particles to exchange positions. For two species it is shown that the moving grains converge to a unique distribution along the vertical scale. For more than two species it is shown that at least one equilibrium distribution exists (there are examples with multiple equilibria). For a class of models with simple competition laws, uniqueness of the equilibrium in all dimensions is shown.
Z/E isomerization of poly‐para‐phenylenevinylene model compounds
2001-06-28

Abstract The poly‐ para ‐phenylenevinylene (PPV) model compound 1 with cyano groups on the vinylene moieties and 2‐ethylhexyloxy chains on the central phenylene unit has been synthesized by Knoevenagel condensation of 1,4‐bis(cyanomethyl)‐2,5‐bis(2‐ethylhexyloxy)benzene and benzaldehyde. The only isomer that was obtained has been identified to have the Z,Z configuration. UV irradiation of the Z,Z isomer 1a in solution with a medium‐pressure mercury lamp gave a mixture of all three possible isomers ( Z,Z, Z,E and E,E ; 1a , 1b and 1c respectively). The isomers were separated by column chromatography and identified spectroscopically. Electrochemical studies and fluorescence emission spectra of 1a and 1c are reported. The substituted PPVs 2, 3 and 4 have been synthesized and their absorption and emission spectra before and after UV irradiation are compared. Copyright © 2001 John Wiley &amp; Sons, Ltd.
Noninvasive detection of coronary lesions by multislice computed tomography: Results of the new age pilot trial
2001-06-29

Abstract The reliable noninvasive assessment of coronary artery disease would constitute an important step forward in clinical cardiology. The aim of the New Age pilot trial was to evaluate the diagnostic accuracy of multislice computed tomography (MSCT) in determining coronary lesions. As a gold standard for in vivo plaque detection, intracoronary ultrasound (ICUS) was used. Forty plaques were detected by ICUS in 15 target vessels (LAD, n = 8; RCA, n = 7) in patients assigned for ICUS‐guided PTCA. Preinterventional MSCT was performed in all patients and the results were compared to ICUS with regard to lesion detection and quantification. According to ICUS results, the 40 plaques were divided into three groups: group I, mild lesions &lt; 50% (n = 14; 44.36% ± 5.77%); group II, intermediate lesions 50%–75% (n = 12; 59.18% ± 9.39%); and group III, severe lesions &gt; 75% (n = 14; 91.47% ± 3.68%). All MSCT scans showed sufficient image quality for analysis. Thirty of 40 (75%) plaques were detected by MSCT in a first blinded session. After unblinding the ICUS results, the remaining 10 (25%) plaques could be identified. Lesion severity was classified correctly in 34 of 40 (85%) plaques. Plaque calcifications were diagnosed correctly in 16 of 19 (84.2%) plaques. Quantification of vessel size revealed a good correlation to the ICUS results (r 2 0.68; P = 0.004). Noninvasive MSCT angiography showed good diagnostic accuracy with regard to lesion detection and quantification of vessel size. The overall good image quality, makes this new technology a promising modality, which might become an alternative diagnostic approach in patients with known or suspected coronary artery disease. Cathet Cardiovasc Intervent 2001;53:352–358. © 2001 Wiley‐Liss, Inc.
Percutaneous coronary interventions using a new 5 French guiding catheter: Results of a prospective study
2001-06-29

Abstract The aim of this prospective study was to analyze the technical feasibility, the success rate, and the special complications of percutaneous coronary interventions (PCIs) using a newly released 5 Fr guiding catheter with an inner diameter of 0.058′′. The study was performed in 150 consecutive patients subjected to coronary angioplasty. In 89% of the patients, the intervention was started with a 5 Fr catheter (JR4 or JL4); in 16 patients a 6 or 7 Fr catheter was used because of unstable clinical conditions according to the decision of the interventional cardiologist. In 12 out of 134 patients, the guiding catheter had to be changed during the intervention from 5 Fr to a 6 or 7 Fr catheter due to poor backup support. In 112 out of 118 patients, the intervention was successfully performed using a 5 Fr catheter (95%); in 12 out of 16 patients, after changing the guiding catheter, the overall success rate was 93%. In patients with type A and B lesions who were initially treated using a 5 Fr catheter, the procedural success rate was 100% (81 out of 81), whereas in patients with type C lesions the procedural success rate was 83% (43 out of 53; P = 0.000053, Fisher's exact test). Furthermore, in patients with a diameter stenosis &lt; 90%, the procedural success rate was 100% (57 out of 57), whereas in patients with a diameter stenosis of 90%–100%, the procedural success rate was 87% (67 out of 77; P = 0.0050). Stent implantation was performed successfully in 24 patients (18%) using the 5 Fr guiding catheter. This study confirms that PCI was technically feasible using a 5 Fr guiding catheter in the majority of consecutive patients with a success rate of 95%. There were significant differences in the success rate depending on the lesion type and the diameter stenosis. Complications were very rare and were not related to the guiding catheter. Limitations of the 5 Fr guiding catheters arose mainly from a poor backup support in long lesions and severe stenosis. Cathet Cardiovasc Intervent 2001;53:308–312. © Wiley‐Liss, Inc.
Femoral revision with the Wagner SL revision stem : evaluation of one hundred and twenty-nine revisions followed for a mean of 4.8 years.
2001-07-01

Because of the encouraging results of implantation of this femoral component with distal fixation, we will continue to use it in the majority of femoral revisions. However, the need for regular follow-up remains, since the rate of complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture, and late infection may increase in the future.
Assessment of porcine bone metabolism by dynamic.
2001-07-01

PET bone studies using [(18)F]fluoride ion provide quantitative estimates of bone blood flow and metabolic activity that correlate with histomorphometric indices of bone formation in the normal bone tissue of the mini pig. Therefore, it seem reasonable to assume that [(18)F]fluoride ion PET can reduce the number of invasive bone biopsies, thus facilitating follow-up of patients with metabolic bone diseases.
Femoral Revision with the Wagner SL Revision Stem
2001-07-01

Background: It is difficult to achieve a successful revision total hip replacement when a patient has severe proximal femoral bone loss. The Wagner SL revision stem has some theoretical advantages, but the durability of this prosthesis is not known. Methods: We reviewed the results of 129 revisions of the femoral component with a Wagner SL revision stem in 123 patients. The indication for revision was aseptic loosening in ninety-seven hips, periprosthetic fracture in thirteen (one of which also had an infection), and septic loosening in sixteen. In the three remaining hips, a Wagner revision stem was inserted during a second-stage reimplantation after the performance of a Girdlestone resection arthroplasty to treat chronic deep infection. The prerevision defects were classified with the system described by Pak et al. as well as with our system. A functional evaluation of the patients and a survival analysis of the revision stems were performed. Results: The mean duration of follow-up was 4.8 years (range, two months to 11.1 years). Six revision stems required repeat revision. With removal of the stem for any cause or the worst case (removal of the stem for any cause and/or lost to follow-up) as the end point, cumulative survival at 11.1 years was 93.9% and 92.8%, respectively. The mean Merle d'Aubigné score improved from 7.7 points preoperatively to 14.8 points at the latest follow-up examination. The most recent radiographs showed good or excellent restoration of the proximal part of the femur in 113 hips (88%). Conclusions: Because of the encouraging results of implantation of this femoral component with distal fixation, we will continue to use it in the majority of femoral revisions. However, the need for regular follow-up remains, since the rate of complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture, and late infection may increase in the future.