julilili42/papers huggingface dataset:
Fast tectonometamorphism and exhumation in the type area of the Barrovian and Buchan zones
2000-01-01

Research Article| May 01, 2000 Fast tectonometamorphism and exhumation in the type area of the Barrovian and Buchan zones G.J.H. Oliver; G.J.H. Oliver 1Crustal Geodynamics Group, School of Geography and Geosciences, St. Andrews University, St. Andrews, Fife, Scotland KY16 9ST, UK Search for other works by this author on: GSW Google Scholar F. Chen; F. Chen 2Institut für Geochemie, Universität Tübingen, Wilhelmstrasse, 56D-72074, Tübingen, Germany Search for other works by this author on: GSW Google Scholar R. Buchwaldt; R. Buchwaldt 3Max-Planck Institut für Chemie Abteilung Geochemie, 55020 Mainz, Germany Search for other works by this author on: GSW Google Scholar E. Hegner E. Hegner 2Institut für Geochemie, Universität Tübingen, Wilhelmstrasse, 56D-72074, Tübingen, Germany Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (5): 459–462. https://doi.org/10.1130/0091-7613(2000)28<459:FTAEIT>2.0.CO;2 Article history received: 21 Oct 1999 rev-recd: 02 Feb 2000 accepted: 16 Feb 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation G.J.H. Oliver, F. Chen, R. Buchwaldt, E. Hegner; Fast tectonometamorphism and exhumation in the type area of the Barrovian and Buchan zones. Geology 2000;; 28 (5): 459–462. doi: https://doi.org/10.1130/0091-7613(2000)28<459:FTAEIT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The beginning of the Grampian episode of tectonometamorphism in Scotland is dated by collision and obduction of the Ballantrae Ophiolite Complex at 478 ± 8 Ma. For the first time we have used zircon and garnet to radiometrically date the peak of the Caledonian Buchan and Barrovian tectonometamorphism in their type areas as contemporaneous at 467 ± 2.5 Ma. Detrital garnet from the neighboring Southern Uplands flysch terrane has the same radiometric age and occurs in 465 ± 2.5 Ma molasse in the Midland Valley. We show that the entire Grampian episode lasted 15 ± 2.5 m.y. and that it took fewer than 7.6 m.y. to expose high-grade rocks following the peak of metamorphism. Those who study Precambrian orogeny should note the brevity of this Scottish tectonometamorphic episode and the speed of exhumation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Mechanisms of speed–accuracy tradeoff: evidence from covert motor processes
2000-01-01

Speed-accuracy tradeoff (SAT) refers to the inverse relation between speed and accuracy found in many tasks. The present study employed reaction times (RTs) and movement-related brain potentials arising during the RT interval (lateralized readiness potentials; LRPs) to examine the mechanisms by which people control their position along an SAT continuum. Many models of SAT postulate that changes in position across conditions (macro-tradeoffs) and trial-by-trial variations within conditions (micro-tradeoffs) are mediated, at least in part, by the same mechanisms. These include: (1) all models that postulate mixtures of guesses and accurate responses and (2) some models postulating decision criterions applied to accumulating evidence or response tendencies. Such models would seem to be rejected for conditions under which macro- and micro-tradeoffs can be shown to involve no stages of RT in common. Under the present conditions, the two types of SAT produced additive effects on RT, with the macro-tradeoff involving only that portion of the RT interval occurring after LRP onset and the micro-tradeoff involving only that portion before LRP onset. These findings imply that the two types of SAT arose during different serial stages of RT and that the macro-tradeoff involved only stages occurring after differential preparation of the two hands had begun.
Differential Activation in Somatosensory Cortex for Different Discrimination Tasks
2000-01-01

Maps of the body surface in somatosensory cortex have been shown to be highly plastic, altering their configuration in response to changes in use of body parts. The current study investigated alterations in the functional organization of the human somatosensory cortex resulting from massed practice. Over a period of 4 weeks, subjects were given synchronous tactile stimulation of thumb (D1) and little finger (D5) for 1 hr/d. They had to identify the orientation of the stimuli. Neuroelectric source localization based on high-resolution EEG revealed that, when subjects received passive tactile stimulation of D1 or D5, the representations of the fingers in primary somatosensory cortex were closer together after training than before. There was also an apparently correlative tendency to anomalously mislocalize near-threshold tactile stimuli equally to the distant finger costimulated during training rather than preferentially to the finger nearest to the finger stimulated in a post-training test. However, when the stimulus discrimination had to be made, neuroelectric source imaging revealed that the digital representations of D1 and D5 were further apart after training than before. Thus, the same series of prolonged repetitive stimulations produced two different opposite effects on the spatial relationship of the cortical representations of the digits, suggesting that differential activation in the same region of somatosensory cortex is specific to different tasks.
MR imaging in the presence of vascular stents: A systematic assessment of artifacts for various stent orientations, sequence types, and field strengths
2000-01-01

A systematic evaluation of the potential quality of magnetic resonance images recorded in the presence of metallic stents was performed on a low-field open imager operating at 0.2 T and on a high-field closed unit operating at 1.0 T. Eight different stent types were examined by two-dimensional gradient-echo sequences with echo times of 4 and 10 msec and by a fast spin-echo technique. In addition, a three-dimensional gradient-echo sequence was applied with an echo time of 2.4 msec. A set of sequence and slice parameters was used on both scanners. Thus, artifacts due to susceptibility effects depending on the magnetic field strength could be distinguished from radiofrequency shielding effects in the lumen of the stents (independent of the field strength). Nine different orthogonal orientations of the stent axis and the image (in terms of slice, read, and phase-encoding direction) were tested, and the artifacts (extension of signal void and visibility of the lumen) were compared. The optimal strategy for visualization of vascular and perivascular regions outside the stents was fast spin-echo imaging with the stent axis and read direction parallel to the static field. Susceptibility-induced signal void in gradient-echo images was minimal using the three-dimensional approach. Increased transmitter amplitudes above usual values provided clearly improved insight in the lumen using gradient-echo sequences.
Clinical and Biologic Diversity of Leukemias Occurring in Patients with Mastocytosis
2000-01-01

Patients with systemic mast cell (MC) disease, but not those with cutaneous mastocytosis, are at a high risk (10-30%) to develop life-threatening myelogenous malignancies. In a significant proportion of cases, myeloid leukemias occur. Using conventional criteria, such leukemias resemble acute myeloid leukemia (AML), chronic myeloid leukemia (CML), or myelomonocytic leukemia (CMML). Mast cell leukemia (MCL) may also occur. Myeloid leukemias (AML, CML, CMML) can develop in indolent or aggressive mastocytosis (skin lesions present or absent) with a variable prephase of MC disease. By contrast, MCL (typically without skin lesions) often develops on a "de novo" basis, and, if at all recognized, a prephase resembling (malignant) mastocytosis, is short. MCL differs from myeloid leukemias (AML, CML, CMML) by morphologic and phenotypic cellular characteristics. In fact, MCL are strongly tryptase-positive, c-kit-positive, myeloperoxidase (MPO) -negative neoplasms with variable metachromasia and chloroacetate esterase expression, whereas an MPO-positive, tryptase-negative phenotype supports the diagnosis of a myeloid non-MC lineage disease. Thus, MCL, but also myeloid non-MC lineage leukemias can develop in patients with (systemic) mastocytosis. Little is known, however, about the pathophysiologic basis of co-evolution. In the present article, the concomitant occurrence of mastocytosis and leukemia is discussed in the light of the literature and of concepts proposed to explain the biologic basis of this phenomenon.
Gold complexes with thiosemicarbazones: reactions of bi- and tridentate thiosemicarbazones with dichloro[2-(dimethylaminomethyl)phenyl-C 1,N ]gold(III), [Au(damp-C 1,N )Cl2]
2000-01-01

Dichloro[2-(N,N-dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2] (1), reacts with salicylaldehyde thiosemicarbazone (H2saltsc), vanilline thiosemicarbazone (Hvantsc), N-methylpyrrole aldehyde thiosemicarbazone (Hmepyrtsc), pyridoxal methylthiosemicarbazone (H2pydoxmetsc), 2-diphenylphosphinobenzaldehyde thiosemicarbazone (HPtsc) or variously substituted acetylpyridine thiosemicarbazones (HapRtsc; R = H, Me, Ph) with cleavage of the Au–N bond and protonation of the dimethylamino group. Compounds of general formulae [Au(Hdamp-C1)Cl(L)]+ (L = Hsaltsc−, vantsc−, mepyrtsc−), [Au(Hdamp-C1)Cl(L)]2+ (L = H2pydoxmetsc) or [Au(Hdamp-C1)(L)]2+ (L = Ptsc−, apRtsc−, R = H, Me, Ph) have been isolated and characterized. The presence of the σ-bonded 2-(dimethylaminomethyl)phenyl ligand is mandatory to prevent reduction of the gold(III) centre. The crystal structures of [Au(Hdamp-C1)Cl(Hsaltsc)](PF6) (3a), [Au(Hdamp-C1)Cl(mepyrtsc)]Cl (3c), [Au(Hdamp-C1)Cl(H2pydoxmetsc)]Cl2·MeOH (4), [Au(Hdamp-C1)(apPhtsc)]Cl2·2 MeOH (5c) and [Au(Hdamp-C1)(Ptsc)]Cl2· 1.5MeOH (6) have been elucidated, showing the gold atoms in distorted square-planar co-ordination environments.
Extreme UV Exposure of Professional Cyclists
2000-01-01

&lt;i&gt;Background:&lt;/i&gt; The most important risk factor for the development of melanoma and non-melanoma skin cancer is thought to be ultraviolet (UV) radiation. To date there is no quantification of the UV exposure of outdoor sports professionals training and competing at high solar UV levels. &lt;i&gt;Methods:&lt;/i&gt; During eight stages of the ‘Tour de Suisse’ cycling race, the UV exposure of 6 professional cyclists was monitored with &lt;i&gt;Bacillus subtilis&lt;/i&gt; spore film dosimeters. &lt;i&gt;Results:&lt;/i&gt; The measurements showed a personal UV exposure between 0.2 minimal erythema dose (MED) during the prologue and 17.2 MED during a mountain stage. The mean daily personal exposure of all full stages (prologue excluded) was 8.1 MED. The personal exposure level determined during these races exceeded international exposure limits by more than 30 times. &lt;i&gt;Conclusion:&lt;/i&gt; Therefore UV exposure of sports professionals should be limited by application of sun screens, protective clothing and training/competition at low insolation.
Coordinated Diurnal Regulation of Low‐ and High‐Affinity Nitrate Transporters in Tomato
2000-01-01

Abstract: Two new members of the NRT2 gene family encoding high‐affinity NO 3 − transporters were isolated from tomato by heterologous screening. Both cDNAs, LeNRT2;1 and LeNRT2;2, are highly similar in the coding region, however, significant nucleotide differences were found in the 3′‐untranslated region. High‐stringent Southern analysis with gene‐specific probes indicated that the two genes are linked in the genome and are most probably derived from a recent gene duplication. Expression of both genes was restricted to roots. Although no difference in expression between both genes could be demonstrated by Northern analysis, LeNRT2;1 and LeNRT2;2 were isolated 56 and 3 times, respectively, from a cDNA library of root hairs, indicating a dominant expression of LeNRT2;1 in root hairs of tomato seedlings. Maximum transcript levels of LeNRT2 peaked 4 h after NO 3 − induction and coincided with those of the putative low‐affinity NO 3 − transporter gene, LeNRT1;2. In contrast, 4 h after NO 3 − supply LeNRT1;1 transcription was maximally repressed, reflecting an opposite regulation. As transcript levels of LeNRT2 also increased independently from NO 3 − induction, diurnal gene expression was monitored. All investigated genes, LeNRT2, LeNRT1;1, LeNRT1;2 and LeNR, showed the highest peak in transcript levels 4 h after the onset of the light period and a second peak at the end of the light period. Although expression of these genes was highly coordinated at these times of the day, LeNRT1;1, LeNRT1;2 and LeNR showed additional peaks. This indicates that diurnal oscillation of these genes is most likely based on multiple factors, such as carbohydrate supply to the roots, feedback regulation from N assimilates and phytochrome‐mediated regulation.
Diversity, growth forms and taphonomy: key factors controlling the fabric of coralline algae dominated shelf carbonates
2000-01-01

Abstract The fabric of biogenic carbonate sediments can be differentiated (1) with respect to diversity of constituent components, (2) using features pertaining to their growth forms and (3) upon consideration of taphonomic aspects. These not only determine limestone fabrics, but also form the basis for facies differentiation and palaeoecological interpretation. This study is based on coralline algae dominated Lower Oligocene shelf carbonates from northern Slovenia from which seven facies (nummulitic, bivalve, foraminiferal-coralline algal, coralline algal, coralline algal-coral, coral and grainstone) are differentiated. The role of diversity, growth forms and taphonomy of coralline algae in each facies is discussed. Nine species from seven genera of coralline algae including geniculates and non-geniculates were recognized. Numerous different growth forms ranging from crusts, protuberances, lamellae to arborescent types are present. A wide range of taphonomic features including disarticulation, encrustation, fragmentation and abrasion can be observed. The determination of diversity is dependent on taxonomic identification using preserved diagnostic characters relevant to palaeontological and botanical systematics. Growth-form determination in thin section is influenced by orientation and sectioning effects. The taphonomy of red algae is highly dependent on initial growth form and the specific environment in which they are found. A number of taphonomic processes described in Recent environments (e.g. disease, shallow grazing) cannot be ascertained in fossil material, while others are readily observable. Some taphonomic processes are detrimental (e.g. fragmentation, abrasion) to the preservation and recognition of vegetative and growth-form features, while others have positive effects (e.g. encrustation).
Purification and characterization of oxidoreductases-catalyzing carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) in human liver cytosol
2000-01-01

1. Four enzymes were purified to homogeneity from human liver cytosol and were demonstrated to be responsible for carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK). 2. Carbonyl reductase (EC 1.1.1.184), a member of the short-chain dehydrogenase/reductase (SDR) superfamily, was compared with three isoenzymes of the aldo-keto reductase (AKR) superfamily in terms of enzyme kinetics, co-substrate dependence and inhibition pattern. 3. AKR1C1, 1C2 and 1C4, previously designated as dihydrodiol dehydrogenases (DD1, DD2 and DD4), showed lower K(m) (0.2, 0.3 and 0.8 mM respectively) than did carbonyl reductase (7 mM), whereas carbonyl reductase exhibited the highest enzyme efficiency (Vmax/K(m)) for NNK. Multiplication of enzyme efficiencies with the relative quantities of individual enzymes in cytosol resulted in a rough estimate of their contributions to total alcohol metabolite formation. These were approximately 60% for carbonyl reductase, 20% each for AKR1C1 and 1C2, and 1% for AKR1C4. 4. Except for AKR1C4, the enzymes had a strong preference for NADPH over NADH, and the highest activities were measured with an NADPH-regenerating system. Carbonyl reductase activity was extensively inhibited by menadione, rutin and quercitrin, whereas medroxyprogesterone acetate, phenolphthalein and flufenamic acid were potent inhibitors of AKR1C1, 1C2 and 1C4. 5. In conclusion, cytosolic members of the SDR and AKR superfamilies contribute to reductive NNK detoxification in human liver, the enzymes responsible being carbonyl reductase and aldoketo reductases of the AKRIC subfamily.
Distribution of mislocalizations of tactile stimuli on the fingers of the human hand
2000-01-01

Sensitivity of the fingers of the two hands to faint tactile stimuli were tested in eight healthy subjects with a von Frey hair in a forced choice point localization test. Frequencies of correct responses were higher on the left than on the right hand, consistent with a right hemispheric advantage for spatial processing. Within the hands, stimulations of the ring fingers resulted in the highest percentage of correct localizations and stimulations of the thumbs in the fewest correct responses. This superiority of the ring fingers is probably related to a higher point pressure sensitivity and does not reflect the relative size of the representational area of the different fingers in the somatosensory cortex. Mislocalizations, i.e., stimuli that were not correctly attributed to the stimulation site, were located in the vicinity of the stimulation site within the finger as well as across fingers. The distribution of mislocalization across fingers deviates from a distribution expected by chance, showing a higher frequency of mislocalizations to the neighboring fingers than to more distant fingers. This observation in humans matches well with electrophysiological evidence from animal studies that some primary somatosensory cortex neurons have receptive fields that are not restricted to a single digit, but rather cover neighboring digits.
May Government Ever Use Torture? Two Responses from German Law
2000-01-01

Journal Article May Government Ever Use Torture? Two Responses From German Law Get access Winfried Brugger Winfried Brugger 1Winfried Brugger is Professor of Public Law and Philosophy of Law, University of Heidelberg, Germany. 1998-99 Visiting Professor, Georgetown University Law Center. J.D. 1973, S.J.D. 1980, University of Tuebingen, Germany; LL.M. 1981, University of California at Berkeley. Search for other works by this author on: Oxford Academic Google Scholar The American Journal of Comparative Law, Volume 48, Issue 4, Autumn 2000, Pages 661–678, https://doi.org/10.2307/840910 Published: 01 October 2000
Identification of tumor-associated MHC class I ligands by a novel T cell-independent approach
2000-01-01

Specific immunotherapy of cancer utilizes tumor-directed cytotoxic T lymphocytes (CTL) that lyse tumor cells presenting MHC class I-associated peptides derived from tumor-associated proteins. Many tumor-associated gene products are known, but corresponding T cell epitopes are only known for relatively few of these. The most commonly used approaches to identify such antigens require pre-existing CTL lines or clones. By using a CTL-independent high performance liquid chromatography mass spectrometry (HPLC MS)-based approach we identified HLA-A2-presented peptides from carcinoembryonic antigen and wild-type p53 with a copy number as low as eight molecules per cell. Potential epitopes were predicted from the sequences of known tumor antigens and the corresponding synthetic peptides were analyzed by nanocapillary HPLC MS. In parallel, peptides were extracted from fresh, solid tumor tissue or tumor cell lines and analyzed in the same way. Upon co-elution of a natural peptide with a predicted peptide of the same mass, the peptide sequence was confirmed by on-line tandem MS. This approach allows rapid screening of large numbers of tumor-associated gene products for naturally processed peptides presented by different MHC class I molecules as a prerequisite for efficient epitope identification and rapid transfer to therapeutic vaccine trials.
Two new tailoring enzymes, a glycosyltransferase and an oxygenase, involved in biosynthesis of the angucycline antibiotic urdamycin A in Streptomyces fradiae Tü2717 This paper is dedicated to Professor Heinz Floss, a pioneer in the field of antibiotics, on the occasion of his 65th birthday. The GenBank accession numbers for the sequences reported in this paper are AF164960 and AF164961.
2000-01-01

Urdamycin A, the principal product of Streptomyces fradiae Tu2717, is an angucycline-type antibiotic and anticancer agent containing C-glycosidically linked D-olivose. To extend knowledge of the biosynthesis of urdamycin A the authors have cloned further parts of the urdamycin biosynthetic gene cluster. Three new ORFs (urdK, urdJ and urdO) were identified on a 3.35 kb fragment, and seven new ORFs (urdL, urdM, urdJ2, urdZl, urdGT2, urdG and urdH) on an 8.05 kb fragment. The deduced products of these genes show similarities to transporters (urdJ and urdJ2), regulatory genes (urdK), reductases (urdO), cyclases (urdL) and deoxysugar biosynthetic genes (urdG, urdH and urdZ1). The product of urdM shows striking sequence similarity to oxygenases (N-terminal sequence) as well as reductases (C-terminal sequence), and the deduced amino acid sequence of urdGT2 resembles those of glycosyltransferases. To determine the function of urdM and urdGT2, targeted gene inactivation experiments were performed. The resulting urdM deletion mutant strains accumulated predominantly rabelomycin, indicating that UrdM is involved in oxygenation at position 12b of urdamycin A. A mutant in which urdGT2 had been deleted produced urdamycin I, urdamycin J and urdamycin K instead of urdamycin A. Urdamycins I, J and K are tetracyclic angucyclinones lacking a C-C connected deoxysugar moiety. Therefore UrdGT2 must catalyse the earliest glycosyltransfer step in the urdamycin biosynthetic pathway, the C-glycosyltransfer of one NDP-D-olivose.
Cross‐talk between ammonium transporters in yeast and interference by the soybean SAT1 protein
2000-01-01

Ammonium uptake in the yeast Saccharomyces cerevisiae involves three membrane transporters (Mep1, ‐2 and ‐3) belonging to an evolutionarily conserved protein family that also includes the rhesus (Rh) blood group polypeptides of erythrocytes. We show here that, in the 26972c mutant defective in NH 4 + transport, the Mep1 protein carrying an amino acid substitution in its cytoplasmic C‐terminus trans ‐inhibits the closely related Mep3 protein. The same mutation introduced into Mep3 leads to loss of transport activity and this inactive form also trans ‐inhibits native Mep3. Inhibition of Mep3 is post‐translational and can be overcome by overexpression. These results are consistent with a direct interaction between Mep proteins, as is the case for the Rh polypeptides. The soybean GmSAT1 gene, recently cloned for its ability to complement the NH 4 + transport defect of strain 26972c, has been described as an NH 4 + channel protein involved in the transfer of fixed nitrogen from the bacteroid to the host plant. We show here that GmSAT1 contains a sequence homologous to the DNA‐binding domain of basic helix–loop–helix (bHLH) transcription factors. We also show that GmSAT1 restores NH 4 + uptake in the yeast mutant by interfering with the inhibition of Mep3. Our results are not consistent with a direct role of GmSAT1 in ammonium transport.