julilili42/papers huggingface dataset:
Local mechanisms in sex specific morphogenesis
2000-01-01

Sex determination in mammals occurs on three levels. Segregation of sex chromosomes determines the chromosomal sex. Sry on the Y chromosome induces formation of a testis which in turn regulates via AMH and testosterone the development of the genital tract and the external phenotype. Recently a number of new factors have been described, which affect sexual development but have not yet found a place in the above canonical scheme of sex determination. For the purpose of this review, the factors are aligned according to their quality as transcription factors, steroid hormones, or growth factors. In this web of regulatory factors, the classical sex determining factors have evolved as master mechanisms while others function as slaves, or were totally suppressed. In this context, androgens acquired a dominant role in mammalian development. Androgens determine the morphogenesis of the genital tract. The effects of androgens are mediated by local cellular interactions. In the cranial section of the Wolffian duct the androgen receptor appears in the epithelium and mediates maintenance of the duct via an epithelial factor. In the caudal section of the duct the androgen receptor is expressed in the embryonic mesenchyme. Vesicular glands are induced via a morphogenetically active mesenchymal condensation, while the epithelial buds are primarily AR androgen receptor negative. The dominant role of androgens and formation of a vagina evolved together at the transition to eutherian mammals. Under this aspect, the role of androgens in the development of the vagina is analyzed.
R- and B-cadherin expression defines subpopulations of glial cells involved in axonal guidance in the optic nerve head of the chicken
2000-01-01

Glial cells play a crucial role in the organization and function of the nervous system. Cell-cell adhesion receptors of the cadherin family have been shown to participate in distinct morphogenetic processes throughout the development of the CNS, but little is known about glial expression of cadherins. Applying immunofluorescence and confocal laser scanning microscopy, we investigated R- and B-cadherin expression in relation to the glial cell differentiation in the optic nerve head and pecten oculi of developing chicken. Throughout embryonic development, R- and B-cadherin were expressed in distinct cell populations, which differentiated into distinct subtypes of glial cells. R-cadherin was located in the glia limitans perivascularis et superficialis of the optic nerve and in cells bordering the optic nerve head, where it comes in contact with the retina. B-cadherin was located in the glia limitans perivascularis et superficialis of the pecten oculi and in a subset of cells at the retinal border. R-cadherin-expressing cells differentiated unequivocally into a glial fibrillary acidic protein (GFAP)-positive but glutamine synthetase (GS)-negative phenotype, whereas B-cadherin-expressing glia developed into a GS-positive but GFAP-negative phenotype. In addition, the B-cadherin-positive population developed into a highly pigmented cell type, which was consistently associated with pecten-type capillaries. By contrast, the R-cadherin-positive glia remained unpigmented and surrounded normal brain-phenotype capillaries. These data suggest that glial cells, like neurons, may use the expression of different cadherins to segregate and differentiate into distinct subtypes, which goes hand in hand with their involvement in special functions and morphogenetic processes. To address this issue, we selectively lysed both glial subtypes in developing embryos by microinjection of R- and B-cadherin antibodies with complement. First evidence is presented for R-cadherin-positive glial cells as crucial to the organization of the optic nerve and axonal guidance at its lateral margin. B-cadherin-positive cells are involved in the axonal guidance at the pecteneal margin, avoiding the ingrowth of axons into the pecten.
X-Ray structures and ab initio study of the conformational properties of novel oxazole and thiazole containing di- and tripeptide mimetics †
2000-01-01

X-Ray crystal structures of Boc-protected derivatives of the novel di- and tripeptide mimetics 2-aminomethyl-1,3-oxazole-4-carboxylic acid, 2-aminomethyl-1,3-thiazole-4-carboxylic acid, 2-(2′-aminomethyl-1′,3′-oxazol-4′-yl)-1,3-thiazole-4-carboxylic acid (gly(OxaThz)), and 2-(2′-aminomethyl-1,3-thiazol-4′-yl)-1,3-thiazole-4-carboxylic acid (gly(ThzThz)) have been determined. Furthermore conformational properties of the bicyclic compounds have been investigated by ab initio calculations at the HF and DFT level. According to the calculations for the bicyclic compounds the anti conformation is energetically more stable by about 20 kJ mol−1 (HF/6-31G(d)) for gly(ThzThz) and gly(OxaThz) while in the case of gly(ThzOxa) the difference is only about 4 kJ mol−1. The rotational barrier is about 28 kJ mol−1 for the anti→syn conversion. Calculations at the DFT level with a 3-21G(d) basis set yielded similar results.
Identification of trifluoperazine metabolites using HPLC-NMR of test mixtures
2000-01-01

The metabolites of the antipsychotic drug trifluoperazine (TFP) were investigated with on-line coupling of high-performance liquid chromatography (HPLC) and NMR spectroscopy. A chromatographic method was developed using a reversed-phase C30 silica gel column. Rats were given a cumulative dose of 90 mg kg−1 TFP dihydrochloride and samples of brain and muscle tissues were extracted after 29 h. The peaks obtained on chromatographic separation were assigned to trifluoperazine and its metabolites. With the help of chromatograms obtained from test mixtures, 1D and 2D HPLC–NMR were used to identify the peaks found for these mixtures. Copyright © 2000 John Wiley & Sons, Ltd.
The amplitude differences between CCD and PMT measurements
2000-01-01

Using model atmospheres, quantum efficiency and transmission curves, we compute expected values for amplitudes of DAV, DBV and DOV stellar models as measured through different detectors and/or filter combinations.We conclude that choosing the wrong detector may lead to amplitudes lower by 20 % than those measured by phototubes.The correct choice of CCD + filter may reduce this problem down to a difference of 6 %.
Theory refinement and Natural Language Learning
2000-01-01

This 1)aI)er l)resents a learning system for identifying synta(:tie structures.This system relies on the use of backgromld knowledge an(1 default wflues in order to buihl utl an initial grammar and the use of theory retiimlnent in order to iml)rove this granunar.This contbilmtion provides a good machine learning fl:amework for Natural Lmlguage Learning.We illustrate this 1)oint with the 1)resentation of ALLiS, a learlfiug system which generates a regular ext)ression grmnmar of non-recursive phrases fi'om bracketed corpora.
Retrospective diagnosis of trisomy 15 in formalin-fixed, paraffin-embedded placental tissue in a newborn girl with Prader-Willi syndrome
2000-01-01

Paternal deletion of 15q11-q13 and maternal uniparental disomy (UPD) of chromosome 15 are the main causes of Prader-Willi syndrome (PWS). The finding of an UPD(15) is associated with increased maternal age. We present a retrospective diagnosis of a trisomy 15 mosaicism confined to the placenta (CPM) after birth of a girl with clinical features of PWS born to a 43-year-old mother. Chromosome analysis after amniocentesis, performed because of advanced maternal age, had shown a normal female karyotype. In peripheral blood cells molecular studies showed the absence of the paternal allele at the SNRPN locus and fluorescence in situ hybridization (FISH) analysis excluded a deletion of the SNRPN locus on both chromosomes 15. Trisomic cells were detected by FISH on nuclei isolated from formalin-fixed, paraffin-embedded placental tissue using a DNA-probe specific for the centromeric region of chromosome 15.
INTERNAL DESYNCHRONIZATION OF THE CIRCADIAN ACTIVITY AND FEEDING RHYTHM IN AN OWL MONKEY (AOTUS LEMURINUS GRISEIMEMBRA): A CASE STUDY
2000-01-01

In the free-running circadian locomotor activity rhythm of a 7-year-old male owl monkey (Aotus lemurinus griseimembra) kept under constant light and climatic conditions (LL 0.2 lux, 25 degrees C +/- 1 degrees C, 60 +/- 5% relative humidity [RH]), a second rhythm component developed that showed strong relative coordination with the free-running activity rhythm of 24.4h and a 24h rhythm. The simultaneously recorded feeding activity rhythm strongly resembled this rhythm component. Therefore, it seems justified to infer that there was an internal desynchronization between the two behavioral rhythms or their circadian pacemakers, that is, between the light-entrainable oscillator located in the suprachiasmatic nuclei (SCN) and a food-entrainable oscillator located outside the SCN. This internal desynchronization may have been induced and/or maintained by a zeitgeber effect of the (irregular) 24h feeding schedule on the food-entrainable oscillator. The weak relative coordination shown by the activity rhythm indicates a much weaker coupling of the light-entrainable oscillator to the food-entrainable oscillator than vice versa.
The medical engineering program of Forschungszentrum Karlsruhe
2000-01-01

The research activities of the Forschungszentrum Karlsruhe on minimally-invasive surgery (MIS) have for several years improved techniques and instrumentation for different types of MIS. Many types of instruments and robotic devices have been developed and new techniques implemented. In this paper we present the most recent results from our different projects, such as endoscopic heart surgery, tracking systems, a camera guidance device, telemanipulator systems, minimally-invasive breast biopsy in closed-bore MRI, endoscopic training simulators and developments using smart materials (e.g. Nitinol).
Frequent D-loop polymorphism in mtDNA enables genotyping of 1400-year-old human remains from Merowingian graves.
2000-01-01

Improvements of DNA extraction and amplification techniques presently enable DNA analysis of ancient DNA (aDNA) from samples which range from several hundred years of age up to possibly 5000 years. Taking advantage of the abundance of mitochondrial DNA and its polymorphic D-loop sequence, ten individuals from multiple burial sites of the Merowingian culture (South Germany), estimated to be about 1400 years old, were genotyped to determine possible kinship. Moreover, gonosomal DNA markers from the X- and Y-chromosome were applied for sex determination of the remains. In all individuals investigated, deviations from the Anderson mtDNA consensus sequence were observed, all representing substitutions (7 transitions and 3 transversions). Although such mutations have been reported from recent populations, our study constitutes the first description of these mtDNA mutations from numerous aDNA samples recovered from multiple burial sites. The results obtained by molecular anthropology can aid in describing kinship relations and burial customs of ancient remains.
Acute Regulation of the Betaine/GABA Transporter BGT-1 Expressed in Xenopus Oocytes by Extracellular pH
2000-01-01

Besides uptake of Na&lt;sup&gt;+&lt;/sup&gt; and Cl&lt;sup&gt;–&lt;/sup&gt;, mammalian cells counteract osmotic cell shrinkage also by Na&lt;sup&gt;+&lt;/sup&gt;-coupled uptake of osmolytes, e.g., &lt;i&gt;myo&lt;/i&gt;-inositol, taurine or betaine. The expression of the corresponding transporters is transcriptionally regulated by the ambient pH and osmolarity and is increased upon cell shrinkage, a process requiring hours. The present study has been performed to disclose rapid regulation by pH of osmolyte transport via BGT-1. Transport of GABA was investigated by using the two-electrode voltage-clamp technique with BGT-1 expressing Xenopus oocytes. GABA was used as a substrate, because of the low oocyte endogenous transport activity. Extracellular acidification to pH 5.5 reversibly decreased and extracellular alkalinization to pH 8.5 increased GABA-induced currents. Kinetic analysis revealed that extracellular alkalinization increases the affinity for Cl&lt;sup&gt;–&lt;/sup&gt; as reflected by a decrease of the apparent K&lt;sub&gt;m&lt;/sub&gt;-value for Cl&lt;sup&gt;–&lt;/sup&gt; from &gt;500 m&lt;i&gt;M&lt;/i&gt; to 55.8 ± 4.7 m&lt;i&gt;M&lt;/i&gt; upon an increase of the pH from 7.0 to 8.5. The apparent K&lt;sub&gt;m&lt;/sub&gt;- values for Na&lt;sup&gt;+&lt;/sup&gt; and GABA remained unaltered in the pH range from 6.0 to 8.5. Instead, alkalinization increased the maximal current induced by saturating Na&lt;sup&gt;+&lt;/sup&gt; and GABA concentrations. The results are compatible with a model of interference of H&lt;sup&gt;+&lt;/sup&gt; ions with Cl&lt;sup&gt;–&lt;/sup&gt; binding and a pH-dependent reduction of V&lt;sub&gt;max&lt;/sub&gt; for Na&lt;sup&gt;+&lt;/sup&gt; and GABA.
More on b-injectors of sporadic groups+
2000-01-01

A B-Injector in an arbitrary finite group G is defined as a maximal nilpo-tent subgroup of G, containing a subgroup A of G of maximal order satisfying class(A) ≥ 2. Among other results the B-Injectors of the sporadic groups J1,J2,J4, M24 are determined.
Edible tubers formed by roots of Juncus microcephalus Kunth in H.B.K.
2000-01-01

Abstract The roots of the neotropical species Juncus microcephalus form tubers with swollen cortical parenchyma, whose cells are densely filled with starch grains in loose groups. Storage tubers formed by roots are documented here for the first time for a member of Cyperales. According to Honduranian students the tubers are edible, representing a potential crop new to science.
Approaching the grammar of adjuncts : proceedings of the Oslo conference, September 22 - 25, 1999
2000-01-01

The present volume collects the revised and updated versions of papers presented and discussed at the international conference "Approaching the Grammar of Adjuncts", which was held from September 22 to 25, 1999, in Oslo.
Target architecture oriented high-level synthesis for multi-FPGA based emulation
2000-01-01

Article Free Access Share on Target architecture oriented high-level synthesis for multi-FPGA based emulation Authors: Oliver Bringmann FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany and Universität Tübingen, Sand 13, 72076 Tübingen, Germany FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany and Universität Tübingen, Sand 13, 72076 Tübingen, GermanyView Profile , Carsten Menn FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, GermanyView Profile , Wolfgang Rosenstiel FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany and Universität Tübingen, Sand 13, 72076 Tübingen, Germany FZI, Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany and Universität Tübingen, Sand 13, 72076 Tübingen, GermanyView Profile Authors Info & Claims DATE '00: Proceedings of the conference on Design, automation and test in EuropeJanuary 2000 Pages 326–332https://doi.org/10.1145/343647.343790Online:01 January 2000Publication History 1citation201DownloadsMetricsTotal Citations1Total Downloads201Last 12 Months4Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF
Unit cell determination of 2,3,9,10,16,17,23,24- octapentoxyphthalocyanine and its nickel derivative using electron and X-ray powder diffraction
2000-01-01

2,3,9,10,16,17,23,24-Octapentoxyphthalocyanine and its nickel derivative have been studied by means of electron and X-ray powder diffraction. The results reveal that the metal-free compound forms monoclinic crystals (space group C2/c) with unit cell constants a = 4.202 nm , b = 0.4977 nm , c = 3.345 nm , β = 98.9 ° and Z = 4 molecules per unit cell. 2,3,9,10,16,17,23,24-Octapentoxyphthalocyaninatonickel(II) is likely to be isomorphous to its metal-free analogue, but occurs in a second phase which is also stable at room temperature. This is identified to be a crystalline primitive hexagonal phase with cell constants a = b = 2.50 nm and c = 0.33 nm . It is assumed that the molecules form a columnar structure along the c-axis, whereas the hexagonal cross-section in the ab-plane goes back to the molecular disc shape. Imaging of monoclinic crystals of 2,3,9,10,16,17,23,24-octapentoxyphthalocyanine in an energy-filtering transmission electron microscope (EFTEM) can be performed to resolve 2 nm structures only, owing to specimen damage. According to the diffraction pattern, the micrograph provides a view along [001] and shows directly that the structure can be described in terms of parallel columnar stacks of molecules along the b-axis, the distance between neighbouring stacks being [Formula: see text]. The results show that the structures of both the metal-free compound and its nickel analogue are dominated by π–π interactions between the macrocycles, which is a marked difference from the structures of 1,4,8,11,15,18,22,25-octasubstituted phthalocyanines.
Anti-endotoxin antibodies in human milk: correlation with infection of the newborn
2000-01-01

Breast milk contains anti-endotoxin antibodies. The particularly high levels of antiendotoxin antibodies in cases of neonatal infection may present a special maternal protection for premature infants.
Synthesis and Properties of a-Thiagra. A Substituted 5-(2-Thienyl)pyrazolo[4,3-d]pyrimidin-7-one Bioisostere of Viagra®
2000-01-01

For structure-activity manipulations, the compound α-thiagra (3), a thiophene bioisostere of viagra ® , has been prepared and its X-Ray structure determined.The crystallographic data show that the thiophene and pyrazolo[4,3-d]-pyrimidone hetero-ring systems are nearly coplanar by virtue of an adequate intramolecular hydrogen-bond between the pyrimidone NH and the oxygen lone pair of the 3'-ethoxy group.
Comparison of the effects of continuous combined and sequential combined medroxyprogesterone acetate–estradiol treatment on the proliferation of MCF-7 cells*
2000-01-01

The results demonstrate the importance of considering in vivo factors in an in vitro model with regard to improving the cell culture techniques used, to obtain a clearer picture of the possible mechanisms involved in the potential breast cancer risk with different HRT regimens.
Inhibition of CD95/Fas-Induced DNA Degradation by Osmotic Cell Shrinkage
2000-01-01

Apoptosis (programmed cell death) is an active physiological mechanism from which removal of abundant or potentially harmful cells follows. Apoptosis of lymphocytes is critical for the development of the immune system and during the immune response. As we have shown previously, moderate osmotic cell shrinkage interferes with CD95(Fas/Apo-1)-induced cell death. The present study has been performed to further elucidate the underlying mechanisms. To this end, apoptosis in Jurkat T-lymphocytes was elicited by triggering the CD95-receptor with monoclonal CD95/Fas-antibody. Osmotic cell shrinkage which was induced by the addition of 100 mM NaCl, did not significantly interfere with CD95-induced phosphatidylserine exposure nor the activation of caspase 3 activity as determined by PARP cleavage, DEVD-AMC consumption, or the activation of PAK2-kinase. However, osmotic cell shrinkage almost abolished CD95-induced DNA fragmentation (as revealed by propidium iodide staining) and the activation of a DNase as evidenced from SDS-PAGE gel assay. Western blot analysis showed CD95-induced tyrosine phosphorylation of a nuclear protein of ca. 20 kD which comigrated with nuclease activity. This tyrosine phosphorylation was almost completely abolished by the addition of 100 mM NaCl. Furthermore, osmotic cell shrinkage blunted the CD95-induced activation of the Src-like kinase p56lck. It is concluded that different signaling pathways mediate FITC-Annexin-V binding and DNase activation. Only the latter is sensitive to osmotic cell shrinkage.
Additive antioxidative effect of hormone replacement therapy combined with a statin.
2000-01-01

In treating postmenopausal women both statins and estrogens have been shown to elicit favourable effects on lipids and lipoproteins. In addition direct beneficial effects of these substances on the vascular wall are discussed. However, progestin addition to estrogen replacement therapy, which is mandatory in women with an intact uterus. is thought to deteriorate at least partly estradiol-induced direct effects on the vasculature. Oxidation of LDL, which mainly takes place in the vessel wall, seems to be a crucial step in the development of atherosclerosis. Therefore, for the first time, the effect of a statin and an estrogen/progestin combination on the in vitro oxidation of human LDL was investigated comparing the monosubstances fluvastatin. 17beta-estradiol and norethisterone acetate (NETA) as well as the effect of the combination. LDL was isolated from human female serum and oxidation was initiated by copper(II)-chloride. The progression of LDL oxidation was monitored spectrometrically at 234 nm for 300 min. Fluvastatin significantly delayed the onset of LDL oxidation (controls = 85 min) by 21 min at 1 microM, by 99 min and by 210 min at 5 and 10 microM. respectively. 17beta-estradiol significantly reduced the onset by 73 min at 1 microM and by more than 300 min at 5 and 10 microM. NETA had no significant effect. The combination of I microM 17beta-estradiol and 1 microM fluvastatin with 1, 5 and 10 microM NETA showed an additive antioxidative effect of estradiol and fluvastatin and no deterioration by the addition of NETA even at high dosages. It can be concluded that treatment of postmenopausal women with fluvastatin and a combination of 17beta-estradiol with NETA may have not only beneficial effects on lipid disorders but may also elicit a direct potent antiatherosclerotic action on the vasculature.
Mizar Formalization of Concept Lattices
2000-01-01

Abstract – In this paper we report on the Mizar codification of formal concepts and concept lattices being part of the theory of formal concept analysis, a mathematical theory that formally describes the notion of concepts and concept hierarchies. We give a short introduction to the theory of concept lattices and describe how we modelled these structures in the Mizar language. After that we discuss experiences and problems concerning the formalization; in particular we deal with reusing mathematical knowledge stored in the Mizar Mathematical Library.
Randomized Point Sampling for Output-Sensitive Rendering of Complex Dynamic Scenes
2000-01-01

We present a new output-sensitive rendering algorithm, the randomized z-buffer algorithm. It renders an image of a three dimensional scene of triangular primitives by reconstruction from a random sample of surface points which are chosen with a probability proportional to the projected area of the objects. The approach is independent of mesh connectivity and topology. It leads to a rendering time that grows only logarithmically with the numbers of triangles in the scene and to linear memory consumption, thus allowing walkthroughs of scenes of extreme complexity. We consider different methods for image reconstruction which aim at correctness, rendering speed and image quality and we develop an efficient data structure for sample extraction in output-sensitive time which allows for efficient dynamic updates of the scene. Experiments confirm that scenes consisting of some hundred billion triangles can be rendered within seconds with an image quality comparable to a conventio...