julilili42/papers huggingface dataset:
Chromatography a Century of Discovery
2001-12-01

is a documentary of seminal events, developments, discovery, and history of chromatography in the 20th century. Its central theme is the impact of chromatography as a branch of science on different facets of science - analytical chemistry, instrumentation, biomedical, environmental, pharmaceutical, and space sciences etc.: This submission is a preprint of the chapters that complement the material contained within a book of the same title published by Elsevier Science (ISBN 0-444-50114-2). The printed volume has Chapters 1 to 7; the chapters S-7 to S-15 and appendices are found in this submission on the CPS. Please download the main full-text PDF to obtain a comprehensive table of contents and preface to the book. The chapters may be downloaded from the supplementary files section.
Usage-based visualization of web localities
2001-12-01

The World-Wide Web has evolved into an extremely huge but &amp;quot;messy&amp;quot; information space which is hard to overview. Sitemaps as alternative views of Web sites have been proposed to assist the user in navigating the hyperspace. As Web localities are subject to frequent change and redesign, it is especially important to provide a system for automatic generation of such sitemaps from various data sources instead of creating them manually. In this paper we present a new usage-based navigation sitemap approach. We elaborate the necessary concepts of data extraction and path visualizations. Finally, we demonstrate the results of our implementation using the yFiles.
Hydrops fetalis in three male fetuses of a female with incontinentia pigmenti
2001-12-01

Abstract Objectives Careful investigation of hydrops fetalis (HF) is important with regard to genetic counselling and prenatal diagnosis. HF is known to be associated with various genetic disorders. To date there has been only one report of a male fetus in whom incontinentia pigmenti (IP) was associated with generalised oedema. We describe a family who had a girl with clinical signs of IP after three consecutive miscarriages of three male fetuses due to HF. Results Molecular genetic analysis showed a mutation in the NEMO/IKKχ gene in the girl and the mother, which confirmed the diagnosis of IP in both cases. In the two fetuses that could be investigated, inheritance of the affected maternal X chromosome could be demonstrated retrospectively by linkage analysis. Conclusion The present findings suggest that IP might be an X‐linked dominant trait causing HF in male fetuses. In cases of recurrent HF in male fetuses, minimal signs of IP in the maternal line should therefore be carefully investigated in order to be able to perform mutational analysis and to offer appropriate genetic counselling. Copyright © 2001 John Wiley &amp; Sons, Ltd.
Induction of Bile Ducts in Embryonic Liver by Mesenchyme: A New Perspective for the Treatment of Biliary Atresia?
2001-12-01

Presently only those forms of Extrahepatic Biliary Atresia (EHBA) with minimal or no intrahepatic manifestations can be treated successfully by extensive hepatoportoenterostomy. Intraoperative macro- and microscopic observations show that the typical pathogenetic manifestations in EHBA are most prominent at the porta hepatis. We therefore postulate that EHBA is the result of a defective embryonic development of the porta hepatis. In rat embryos hepatic bile duct formation is initiated at the porta hepatis and in this context mesenchyme from the periportal region seems to play a major inductive role. In order to demonstrate the role of invading periportal mesenchyme for the process of bile duct rudiment formation we established an organ culture model of the embryonic porta hepatis by recombining periportal mesenchyme with peripheral liver fragments from 15 days old rat embryos (Carnegie Stage 21). The degree of mesenchyme invasion as well as the formation of mesenchyme-surrounded liver cell clusters, rosettes or vesicles (bile duct rudiments) were assessed. Mesenchyme from the porta hepatis invaded the peripheral liver fragments and induced the formation of mesenchyme-surrounded liver cell clusters and rosettes with the beginning of lumen formation. Kidney mesenchyme recombined with liver fragments as a mesenchymal alternative showed almost the same effect, lung mesenchyme showed only a very weak inductive effect. To assess the effect of a diffusible factor versus direct cell contact, a millipore filter with and without paraffin coating was interposed between mesenchyme containing tissue and peripheral liver tissue fragments. Without direct cell contact to mesenchyme no hepatoblast cluster or rosette formation could be observed. Comparing this result to the normal development of the liver in rats our investigations suggest that the embryogenesis of the porta hepatis is probably defined by the following two developmental steps: First, differentiation of the intrahepatic bile duct system which is induced by invading mesenchyme originating from the extrahepatic periportal region and realized by epithelium mesenchyme interaction. Second, fusion of extra- and intrahepatic bile duct systems at the level of the later porta hepatis. Disturbances of this complex process can possibly lead to biliary atresia. Further investigations regarding details of the role of the mesenchyme, its inductive factors and the kidney mesenchyme's inductive potential in liver development may provide a new perspective for future treatment of biliary atresia.
Oxygen-dependent Regulation of in VivoReplication of Simian Virus 40 DNA Is Modulated by Glucose
2001-12-01

Simian virus 40 (SV40)-infected CV1 cells exposed to hypoxia show an inhibition of viral replication. Reoxygenation after several hours of hypoxia results in new initiations followed by a nearly synchronous round of SV40 replication. In this communication, we examined the effect of glucose on inhibition of viral DNA replication under hypoxia. We found that glucose stimulated SV40 DNA replication under hypoxia in two different ways. First, the rate of DNA synthesis, i.e. the fork propagation rate, increased. This effect seemed to be mediated by inhibition of mitochondrial respiration by glucose (Crabtree effect). Inhibition of mitochondrial respiration probably resulted in a higher intracellular oxygen concentration and an activation of oxygen-dependent ribonucleotide reductase, which provides the precursors for DNA synthesis. This glucose effect was consequently strongly dependent on the strength of hypoxia and the extent of intracellular respiration; hypoxic gassing with 10 ppm instead of 200-400 ppm O(2) or treatment of hypoxic cells with a mitochondrial uncoupler (carbonyl cyanide m-chlorophenylhydrazone) reduced the glucose effect on replication, whereas antimycin A, an inhibitor of respiration, increased it. The second effect of glucose concerned initiation, i.e. stimulation of unwinding of the viral origin. This effect was not influenced by the strength of hypoxia or the extent of cellular respiration and seemed, therefore, not to be mediated through a Crabtree effect. No evidence for a direct correlation between the cellular ATP concentration and the extent of SV40 replication under hypoxia was found. The effect of glucose on replication under hypoxia was not restricted to SV40-infected CV1 cells but was also detectable in HeLa cells. This suggests it to be a mechanism of more general validity.
Mimetics of a T Cell Epitope Based on Poly-N-acylated Amine Backbone Structures Induce T Cells in Vitro andin Vivo
2001-12-01

Peptidomimetics of the major histocompatibility complex (MHC) class I-restricted ovalbumin-derived T cell epitope SIINFEKL were generated by replacing parts of the peptide backbone by a poly-N-acylated amine (PAA) backbone with aromatic, heteroaromatic, and pseudoaromatic side chains that branch off of the main chain at the amine nitrogen. The structure of the PAAs was designed to position this side chain in the central epitope anchor pocket of the MHC molecule. A number of biologically active PAAs were found that induced cytolysis by the mouse cytotoxic T cell clone 4G3. Competition experiments with independent peptides that are known to bind to the restricting MHC molecule H-2K(b) suggest that the PAAs are bound by the MHC molecules at the same site as conventional peptide epitopes. The PAAs were active also in vivo and induced primary cytotoxic T cell responses in mice.
Neuroblastoma: Inhibition of Progression (Part II) - Basic Science in Pediatric Surgery -
2001-12-01

In neuroblastoma, amplification of the protooncogene N-myc is the most important molecular characteristic predicting a bad outcome for the patients. Despite the importance of the N-myc gene, little is known about the mechanisms regulating its expression. We found evidence that insulin-like growth factor II stimulates the growth of neuroblastoma in a paracrine fashion. Two neuroblastoma cell lines predominantly expressed IGF-II whereas two other cell lines expressed the IGF-receptor. In a receptor-positive cell line, N-myc expression was enhanced by stimulation with IGF-II. As the growth-stimulating signals of the IGF receptor are transmitted via Ras proteins, inactivation of Ras is one promising tool to prevent the induction of N-myc expression by IGF-II. Treatment of neuroblastoma cells with an inhibitor of the farnesyl-protein-transferase (FPTase) inactivated H-ras protein completely and N-ras protein by more than 50 %. Cell growth of neuroblastoma cells in serum containing medium was clearly diminished by inhibition of FPTase. The growth-promoting effect of IGF-II was reduced to exactly half the amount observed in non-inhibited cells.
Phantom limb pain: a report of two cases
2001-12-01

The efficacy of pre‐emptive analgesia for phantom limb pain is still unclear. It is generally accepted that pre hyphen;amputation pain increases the incidence of phantom and stump pain, even if pre‐emptive analgesia is performed before and during surgery and in the postoperative period. Two cases of traumatic upper limb amputations are described here with no pre‐existing pain. Both received similar antinociceptive treatment by continuous block of the brachial plexus through infusion of ropivacaine 0.375% at 5 ml/h for 10 days. Treatment of case 1 was initiated immediately after surgery; however, this amputee developed intensive phantom limb pain which persisted at 6 months. Early use of the prosthesis after surgery was not possible for this patient. The intensity of phantom limb pain in case 2 decreased significantly after 6 months, even though brachial plexus blockade was not started until 5 weeks post‐trauma. This patient used a functional prosthesis intensively beginning early after amputation. Serial magnetoencephalographic recordings were performed in both patients. Only case 2 showed significant changes of cortical reorganization. In case 1 markedly less cortical plasticity was found. A combination of relevant risk factors such as a painful neuroma, behavioural and cognitive coping strategies and the early functional use of prostheses are discussed as important mechanisms contributing to the development of phantom pain and cortical reorganization.
Ex Vivo Expansion of Normal Progenitor Cells from Acute Myeloid Leukemia Cell-Contaminated CD34+Peripheral Blood Progenitor Cells after Mafosfamide Purging
2001-12-01

The rationale for purging of autologous acute myeloid leukemia (AML) grafts is to eradicate contaminating leukemic cells that might contribute to relapse. However, in vitro purging generally delays post-transplant hematopoietic recovery, thus increasing treatment-related complication rates. Theoretically, this prolonged aplasia might be shortened by the additional transplantation of ex vivo-generated progenitor cells. Therefore, we investigated whether nonleukemic progenitors could be expanded ex vivo from AML cell-contaminated CD34(+) peripheral blood progenitor cell (PBPC) preparations. Nonleukemic CD34(+)-selected PBPC and AML cells (Kasumi-1, KG-1, primary AML blasts) were cultured in cytokine-supplemented liquid culture for up to 19 days. Cells were used either unmanipulated or following in vitro purging with mafosfamide (30, 50, 75 microg/ml). Ex vivo-generated cells were assessed by flow cytometry, progenitor cell assays, and polymerase chain reaction. Without prior purging, ex vivo culture markedly amplified AML cells as well as nonleukemic CD34(+) PBPC (day 12: Kasumi-1, 18.5 +/- 0.6-fold; KG-1, 52.2 +/- 2.6-fold; CD34(+), 74.1 +/- 5.6-fold). Co-culture with leukemic cells did not affect CD34(+) cell growth and vice versa. Following in vitro purging, CD34(+) PBPC were expanded even at the highest mafosfamide dose (day 19: 25 +/- 15-fold), whereas leukemic cells were markedly depleted (approx. 1.5 log). Furthermore, normal colony-forming units (CFU) could be effectively recovered (day 19: 10 +/- 3.1% of prepurging input CFU), whereas CFU-L were depleted to undetectable levels in six of seven experiments. Finally, leukemic cells were undetectable following ex vivo co-culture of purged cells (CD34(+) PBPC plus 10% Kasumi-1 cells or primary blasts), but were clearly detectable without purging. Taken together, these data demonstrated that ex vivo expansion of normal progenitors from mafosfamide-purged AML cell-contaminated grafts might be feasible.
Oxidizing Polymers: A Polymer-Supported, Recyclable Hypervalent Iodine(V) Reagent for the Efficient Conversion of Alcohols, Carbonyl Compounds, and Unsaturated Carbamates in Solution J.R. gratefully acknowledges generous support from Prof. M. E. Maier, Tübingen, the Strukturfonds of the University of Tübingen, the Fonds der Chemischen Industrie, and the DFG. We thank Graeme Nicholson, Dietmar Schmid, and Daniel Bischoff for analytical support.
2001-12-03

The oxidation of various alcohols and cyclization of an olefinic carbamate succeeds with the first polymer-supported iodine(V) reagent (see scheme). The novel oxidizing polymer oxidizes sensitive and complex alcohols, including protected amino alcohols, efficiently in good to excellent yields. In addition, the α,β-dehydration of a ketone is demonstrated.
Structural Studies of an Array of Mixed Diamine Phosphine Ruthenium(II) Complexes1
2001-12-04

Treatment of RuCl2(η2-Ph2PCH2CH2OCH3)2 with various chelating diamines permitted the isolation of the corresponding RuCl2(η1-Ph2PCH2CH2OCH3)2(diamine) complexes in high yield (diamine = 1,2-diaminoethane, 1,2-diaminopropane, 1,3-diaminopropane, 1,2-phenylenediamine, 1,8-diaminonaphthalene, 2,2'-bipyridine, 1,10-phenanthroline). In solution, all complexes prefer the trans-chloro cis-phosphine arrangement, as deduced by NMR spectroscopy. X-ray studies showed that in the solid state all three possible isomers of the octahedral RuCl2P2(diamine) complexes are present. The reaction of the RuCl2(η1-Ph2PCH2CH2OCH3)2(diamine) complexes with 1 equiv of AgSbF6, AgBF4, or TlPF6 leads to the abstraction of one chloride by simultaneously coordinating one ether oxygen to ruthenium and forming monocationic [RuCl(η1-Ph2PCH2CH2OCH3)(η2-Ph2PCH2CH2OCH3)(diamine)]+ compounds. If a large excess of silver or thallium salt is used, the dichloro complexes are converted to the [Ru(η2-Ph2PCH2CH2OCH3)2(diamine)]2+ dications. In the case of 1,2-phenylendiamine as coligand, the corresponding dication is only observed in traces. NMR spectroscopic investigations and X-ray structural analyses confirm the η1 and η2 coordination of the ether−phosphine ligands in the corresponding mono- and dicationic ruthenium(II) complexes.
Hollow Accretion Columns on Neutron Stars and the Effects of Gravitational Light Bending
2001-12-10

This study investigates the beam patterns for radiation originating in a hollow column on a slowly rotating neutron star where the Schwarzschild metric is appropriate for calculating photon paths. The beam pattern of a hollow column is the sum of contributions from the two emitting surfaces on the inside and the outside of the column, which combine into a two-component beam pattern. The shapes of the inside beam pattern, the outside beam pattern, and the combined beam pattern are studied for radial cones of different height and width, for isotropic and beamed emission, and for different values of mass and radius of the neutron star. It is argued that the hollow cone model provides an interpretation of the pulse profiles of the X-ray pulsar Centaurus X-3.
Discovery of a Cyclotron Resonance Scattering Feature in the X-Ray Spectrum of XTE J1946+274
2001-12-10

Observations of the transient accreting pulsar XTE J1946+274 made with the Rossi X-ray Timing Explorer during the course of the 1998 September-November outburst, reveal a cyclotron resonance scattering feature (or "cyclotron line") in the hard X-ray spectrum near 35 keV. We determine a centroid energy of 36.2 +0.5/-0.7 keV, which implies a magnetic field strength of 3.1(1+z)x10^12 G, where z is the gravitational redshift of the scattering region. The optical depth, Tau = 0.33 +0.07/-0.06, and width, sigma = 3.37 +0.92/-0.75 keV, are typical of known cyclotron lines in other pulsars. This discovery makes XTE J1946+274 one of thirteen pulsars with securely detected cyclotron lines resulting in direct magnetic field measurements.
X‐Ray Observations of XTE J1550−564 during the Decay of the 2000 Outburst. II. Timing
2001-12-10

We investigate the timing behavior of XTE J1550-564 with the Rossi X-ray Timing Explorer (RXTE) as the source made a transition to the hard state during the decay of the 2000 outburst. We detect a high frequency QPO at 65 Hz in one observation with a fractional rms amplitude of 4.9%. This is the first time that a high frequency QPO has been detected in a transition to the hard state during outburst decay. We also observe low frequency QPOs in the 0.36-4.1 Hz range and rich aperiodic variability. The changes in the temporal properties during the decay are very similar to the state transitions observed for other sources. We find a correlation between the QPO frequency and the break frequency in the continuum power spectra. We investigate the energy dependence of rms amplitudes of the QPOs. We compare these timing properties with those previously observed for XTE J1550-564 and other Galactic black hole candidates and discuss the implications for QPO models and black hole accretion.
Ontogenetic and phylogenetic transformations of the ear ossicles in marsupial mammals
2001-12-12

Abstract This study is based on the examination of histological sections of specimens of different ages and of adult ossicles from macerated skulls representing a wide range of taxa and aims at addressing several issues concerning the evolution of the ear ossicles in marsupials. Three‐dimensional reconstructions of the ear ossicles based on histological series were done for one or more stages of Monodelphis domestica, Caluromys philander, Sminthopsis virginiae, Trichosurus vulpecula, and Macropus rufogriseus . Several common trends were found. Portions of the ossicles that are phylogenetically older develop earlier than portions representing more recent evolutionary inventions (manubrium of the malleus, crus longum of the incus). The onset of endochondral ossification in the taxa in which this was examined followed the sequence; first malleus, then incus, and finally stapes. In M. domestica and C. philander at birth the yet precartilaginous ossicles form a supportive strut between the lower jaw and the braincase. The cartilage of Paauw develops relatively late in comparison with the ear ossicles and in close association to the tendon of the stapedial muscle. A feeble artery traverses the stapedial foramen of the stapes in the youngest stages of M. domestica, C. philander , and Sminthopsis virginiae examined. Presence of a large stapedial foramen is reconstructed in the groundplan of the Didelphidae and of Marsupialia. The stapedial foramen is absent in all adult caenolestids, dasyurids, Myrmecobius, Notoryctes , peramelids, vombatids, and phascolarctids. Pouch young of Perameles sp. and Dasyurus viverrinus show a bicrurate stapes with a sizeable stapedial foramen. Some didelphids examined to date show a double insertion of the Tensor tympani muscle. Some differences exist between M. domestica and C. philander in adult ossicle form, including the relative length of the incudal crus breve and of the stapes. Several differences exist between the malleus of didelphids and that of some phalangeriforms, the latter showing a short neck, absence of the lamina, and a ventrally directed manubrium. Hearing starts in M. domestica at an age in which the external auditory meatus has not yet fully developed, the ossicles are not fully ossified, and the middle ear space is partially filled with loose mesenchyme. The ontogenetic changes in hearing abilities in M. domestica between postnatal days 30 and 40 may be at least partially related to changes in middle ear structures. J. Morphol. 251:219–238, 2002. © 2002 Wiley‐Liss, Inc.
Cytomegalovirus Infection of Extremely Low–Birth Weight Infants via Breast Milk
2001-12-15

In addition to seroprevalence and transmission rate, the clinical symptoms of postnatal cytomegalovirus (CMV) infection in infants with a very low birth weight (VLBW; <1500 g; <32 weeks gestational age at birth) were assessed in a 3-year prospective study. CMV monitoring included serologic testing (of the mother and child) and virus culture and PCR (of samples of both breast milk and the infant's urine). Within 3 weeks of the initial virus detection in the infant, clinical and laboratory parameters were evaluated. Of 170 infants, no CMV transmission was found in the 80 infants of seronegative mothers and in the 3 infants of seropositive mothers who did not shed CMV DNA into breast milk. Transmission occurred in 33 of the 87 CMV-exposed infants, 16 of whom presented with such symptoms as hepatopathy, neutropenia, thrombocytopenia, and sepsis-like deterioration. Low birth weight and early postnatal virus transmission were risk factors for symptomatic infection. VLBW infants of CMV-seropositive mothers are at high risk of acquiring a symptomatic CMV infection postnatally via breast milk.
Retardation of Cochlear Maturation and Impaired Hair Cell Function Caused by Deletion of All Known Thyroid Hormone Receptors
2001-12-15

The deafness caused by early onset hypothyroidism indicates that thyroid hormone is essential for the development of hearing. We investigated the underlying roles of the TRα1 and TRβ thyroid hormone receptors in the auditory system using receptor-deficient mice. TRα1 and TRβ, which act as hormone-activated transcription factors, are encoded by the Thra and Thrb genes, respectively, and both are expressed in the developing cochlea. TRβ is required for hearing because TRβ-deficient ( Thrb tm1/tm1 ) mice have a defective auditory-evoked brainstem response and retarded expression of a potassium current ( I K,f ) in the cochlear inner hair cells. Here, we show that although TRα1 is individually dispensable, TRα1 and TRβ synergistically control an extended array of functions in postnatal cochlear development. Compared with Thrb tm1/tm1 mice, the deletion of all TRs in Thra tm1/tm1 Thrb tm1/tm1 mice produces exacerbated and novel phenotypes, including delayed differentiation of the sensory epithelium, malformation of the tectorial membrane, impairment of electromechanical transduction in outer hair cells, and a low endocochlear potential. The induction of I K,f in inner hair cells was not markedly more retarded than in Thrb tm1/tm1 mice, suggesting that this feature of hair cell maturation is primarily TRβ-dependent. These results indicate that distinct pathways mediated by TRβ alone or by TRβ and TRα1 together facilitate control over an extended range of functions during the maturation of the cochlea.