julilili42/papers huggingface dataset:
Differential Effects of Discrete Subarea-specific Lesions of the Rat Medial Prefrontal Cortex on Amphetamine- and Cocaine-induced Behavioural Sensitization
2000-05-01

The medial prefrontal cortex (mPFC) of the rat is thought to be important for the initiation of behavioural sensitization. Since the mPFC is not a homogenous structure, we attempted to systematically examine the contribution of the different subareas - infralimbic (il), prelimbic (pl), anterior cingulate (cg) - of the mPFC to the induction of sensitization by selectively lesioning these areas or the whole mPFC with quinolinic acid (45 nmol in 0.5 microl). During an initial habituation session only il or whole mPFC lesions reduced spontaneous activity. Lesioned and sham-lesioned animals were then treated every other day with either saline, DL-amphetamine (3 mg/kg), or cocaine (20 mg/kg) for 2 weeks in their home cages and were then challenged with either DL-amphetamine (1.5 mg/kg) or cocaine (10 mg/kg) after 1 day and 2 weeks of withdrawal. None of the lesions affected the development of amphetamine-induced sensitization in any way, as assessed by several behavioural parameters including locomotion and sniffing. In contrast, cocaine-induced sensitization was significantly attenuated by pl and whole mPFC lesions, while il and cg lesions were without effect. These results show a double dissociation of the role of the mPFC in behavioural sensitization. The mPFC seems to be important only for cocaine- but not for amphetamine-induced sensitization, and only the pl area appears to be of relevance for cocaine-induced sensitization. It is suggested that these differences are due to differences in the pharmacological interaction of cocaine and amphetamine with the mesocortical dopamine system, and to the particular anatomical connections of each of the mPFC subregions.
Self-limiting and pattern dependent oxidation of silicon dots fabricated on silicon-on-insulator material
2000-05-01

We present a systematic investigation of the oxidation properties of Si dots fabricated on a silicon-on-insulator (SOI) wafer. Dots with diameters varying from 9 to 81 nm were structured on a SOI wafer. These dots were oxidized in a dry oxygen atmosphere at 700, 850, and 1000 °C. The resulting structures were investigated using a side view transmission electron microscopy (TEM) technique in combination with energy filtered TEM. The dimensions of the residual Si and the grown SiO2 were then extracted from the micrographs and analyzed. The oxidation appears to be retarded as compared to the well-known planar oxidation. At 700 and 850 °C a self-limiting effect is observed as well as a clear pattern dependent oxidation at 850 and 1000 °C. We attribute these effects to stress buildup in the oxide. The critical stress, causing the self-limiting effect, is calculated using a model that considers the decrease of the reaction rate with increasing stress perpendicular to the Si surface.
Intensity modulated photon beams subject to a minimal surface smoothing constraint
2000-05-01

A method to smooth intensity-modulated photon beams is presented which can be applied in conjunction with any optimization algorithm. The method employs an additional soft constraint to minimize the area of the surface defined by the photon fluence.
Preparation and Optical Properties of Oligophenylenevinylene/Perhydrotriphenylene Inclusion Compounds
2000-05-01

The channel inclusion compounds (ICs) formed by perhydrotriphenylene (PHTP) with linear or rod-shaped molecules can be used for investigations of guest–guest interactions and in optoelectronics applications, for which high dichroic ratios and high fluorescence quantum yields are desirable. The preparation and characterization of some novel PHTP ICs formed with oligophenylenevinylenes and substituted derivatives are described and the investigation of their optical properties is reported. Results of polarized fluorescence spectroscopy are shown to confirm the expected high optical dichroism.
Evaluation of Protein S‐100 serum concentrations in healthy newborns and seven newborns with perinatal acidosis
2000-05-01

We measured Protein S‐100 serum levels in 66 healthy newborns during the first week of life and in 7 newborns with perinatal acidosis. Normal values ( n = 66) constantly ranged between 0.66 and 3.33 ug/1 (2.5 and 97.5 percentiles) during the evaluation period. Conclusions : Newborns with signs of hypoxic‐ischaemic encephalopathy (HIE) after perinatal acidosis showed elevated Protein S‐100 serum levels, whereas newborns without these signs had normal concentrations. S‐100 might thus be a marker of central nervous system damage in newborns.
Egg surface structure of three clingfish species, using scanning electron microscopy
2000-05-01

The three eastern Atlantic gobiesocid species Lepadogaster lepadogaster, Apletodon dentatus and Diplecogaster bimaculata share an attachment apparatus consisting of numerous bifurcating filaments that originate at the animal egg pole and are embedded in a mucous layer. The thickness of the mucous layer and zona radiata, and the structure and size of the micropyle vary among the three species. Because of lack of information about egg structure in paracanthopterygians and percomorphs with adhesive demersal eggs, the phylogenetic significance of this character complex remains unclear.
A novel keratin 12 mutation in a German kindred with Meesmann's corneal dystrophy
2000-05-01

A novel missense mutation in the K12 gene leads to MCD in a German kindred. Missense mutations have now been identified within the region encoding the helix initiation motif of the K12 protein in eight of 11 MCD kindreds analysed at the molecular level.
Fluvastatin increases prostacyclin and decreases endothelin production by human umbilical vein endothelial cells
2000-05-01

Fluvastatin, an agent of a class of lipid-lowering drugs, the "statins", significantly enhanced prostacyclin synthesis at the concentrations of 0.1 microM and 1 microM and significantly reduced endothelin production at the concentrations 0.01, 0.1 and 1 microM in cell cultures of human umbilical endothelial veins. Since prostacyclin is a vasodilator and endothelin a vasoconstrictor, fluvastatin may have a significant effect on hemodynamics by favoring the balance towards vasodilation. This mechanism may contribute to the prevention of cardiovascular diseases.
Neurotrophin 3 potentiates glutamatergic responses of IHC afferents in the cochlea in vivo
2000-05-01

Abstract Neurotrophins have traditionally been regarded as slow‐acting signals essential for neuronal survival and differentiation. Recent studies with neuronal slices, cultures and nerve ending preparations have shown that neurotrophins generate acute changes in nerve activity. Among the secondary sensory cells are the inner hair cells (IHC) and taste buds, cells which express the neurotrophic factors necessary for the survival of their innervating neurons. If in these cells neurotrophins acutely affect the nerve activity of their afferent neurons, as in the central nervous system (CNS), this may have important functional implications for the corresponding sensory transduction processes. The neurotrophin NT‐3 has been reported to be expressed in IHCs. We chose an in vivo application system for the microiontophoretic supply of NT‐3 in the subsynaptic region of the IHC. The effect of NT‐3 on spontaneous and evoked afferent cochlear nerve activities in adult guinea pig inner ear was studied. We observed that NT‐3 rapidly increases the spontaneous and glutamate‐evoked firing rate of IHC afferents. Moreover, firing induced by both N‐methyl‐ d ‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA) were specifically enhanced during the presence of NT‐3, a process which was selectively blocked by the tyrosine kinase receptor inhibitor K252a. Because we localized NT‐3 mRNA not only in IHCs but also in the spiral ganglion, we propose that similar to other sensory systems, afferent and autocrine neurotrophin activities may be responsible for survival of cochlear neurons. In addition, NT‐3 in IHCs may operate as a signal‐dependent, intrinsic neuromodulator and/or neuroprotector.
Antibody responses to Plasmodium falciparum: evolution according to the severity of a prior clinical episode and association with subsequent reinfection.
2000-05-01

We measured sporozoite- and total parasite antigen-specific IgG and IgM antibodies before and after treatment in matched groups of Gabonese children who presented with either mild or severe Plasmodium falciparum malaria. We investigated the influence of various parameters on these antibody responses, including clinical presentation, age, and post-treatment reinfection profiles. IgG but not IgM responses were strongly influenced by both clinical and parasitological status. IgG responses to the repeat region of the circumsporozoite protein, which were low at admission, particularly so in those with severe anemia, increased after treatment but showed no association with either age or reinfection profiles. Total parasite antigen-specific IgG responses were strongly influenced by parasitological status, and also differed significantly when segregated according to clinical status at admission, age, and reinfection histories. Most notably, anti-parasite IgG responses measured when children were parasite-free were higher and a good indicator of recent reinfections in those who presented with mild rather than with severe malaria. The profile of responses in the latter group suggests some immune system dysfunction, which may reflect the induction of tolerance to parasite antigens.
Acute Encephalopathy Associated with Vigabatrin in a Six‐Month‐Old Girl
2000-05-01

Summary: Purpose : Vigabatrin (VGB) is a new‐generation anticonvulsant used in the treatment of partial seizures and West syndrome. Side effects of VGB treatment in adults and children are well described. Acute encephalopathy with VGB has recently been reported in eight adults. They developed stupor, confusion, and electroencephalographic abnormalities after starting VGB. Does the acute encephalopathy with VGB also occur in childhood? Methods : We describe a 6‐month‐old girl with infantile Alexander disease with hydrocephalus who developed similar clinical symptoms with apathia, somnolence, and sopor, as well as slowing of the background activity in EEG, 3 days after starting VGB. After exclusion of shunt dysfunction, encephalitis, metabolic dysfunction, and renal failure, VGB was discontinued. Results : During the next 2 days, symptoms subsided, and after 10 days, EEG background activity returned to the one before starting VGB. Conclusions : Acute encephalopathy associated with VGB in children seems to be very rare, but should not be ignored.
Novel Nitrido- and Oxo(phthalocyaninato) Complexes of Molybdenum, Tungsten and Rhenium
2000-05-01

The synthesis of new nitrido(phthalocyaninato)molybdenum (1–4) and -tungsten complexes (5–7) starting from the corresponding phthalonitriles and MNCl3 (M = Mo, W) is reported. In addition, the reaction of (tBu4Pc)WN (6) with PPh3 leading, after several steps, to the diamagnetic compound (tBu4Pc)WO (7) is described. The reaction of (tBu4Pc)ReN (9) with PPh3 leads to [(tBu4Pc)ReO]2 (12), and of [(C5H11)8Pc]ReN (10) with PPh3 leads, under different conditions, to {[(C5H11)8Pc]ReO}2O (11).
Kinetics of soot formation in tetrachloromethane pyrolysis
2000-05-01

Kinetics of soot formation is studied in tetrachloromethane pyrolysis behind shock waves. The time dependences of macrokinetic characteristics of soot particle growth (the induction period, the soot yield, and the apparent rate constant of soot particle growth) are determined. Based on the experimental data, the quantitative model of soot formation is developed for tetrachloromethane pyrolysis behind shock waves. Special attention is paid to the thermal effects in CCl4 pyrolysis.
The discovery of photospheric nickel in the hot DO white dwarf REJ 0503-289
2000-05-01

We present the first evidence for the direct detection of nickel in the photosphere of the hot DO white dwarf REJ 0503-289. While this element has been seen previously in the atmospheres of hot H-rich white dwarfs, this is one of the first similar discoveries in a He-rich object. Intriguingly, iron, which is observed to be more abundant than Ni in the hot DA stars, is not detected, the upper limit to its abundance (Fe/He = 10−6) implying an Fe/Ni ratio a factor of 10 lower than seen in the H-rich objects (Ni/He = 10−5 for REJ 0503-289). The abundances of nickel and various other elements heavier than He were determined from Goddard High Resolution Spectrograph spectra. We used two completely independent sets of non-local thermodynamic equilibrium model atmospheres, which both provide the same results. This not only reduces the possibility of systematic errors in our analysis, but is also an important consistency check for both model atmosphere codes.
Effect of Intracerebral Administration of NMDA and AMPA on Dopamine and Glutamate Release in the Ventral Pallidum and on Motor Behavior
2000-05-01

Abstract: The present study investigates the modulation of the ventral tegmental area (VTA)‐ventral pallidum (VP) dopaminergic system by glutamate agonists in rats. The glutamate receptor agonists N ‐methyl‐D‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionic acid (AMPA) were infused via reversed microdialysis into the VTA, and dopamine (DA), glutamate, and aspartate levels in the VTA and ipsilateral VP were monitored together with motor behavior screened in an open field. NMDA (750 μ M ) infusion, as well as AMPA (50 μ M ) infusion, induced an increase of DA and glutamate levels in the VTA, followed by an increase of DA levels in the ipsilateral VP and by enhanced locomotor activity. The increase of DA in the VP was similar after administration of these two glutamate agonists, although motor activity was more pronounced and showed an earlier onset after NMDA infusion. Glutamate levels in the VP were not increased by the stimulation of DA release. It is concluded that DA is released from mesencephalic DA neurons projecting to the VP and that these neurons are controlled by glutamatergic systems, via NMDA and AMPA receptors. Thus, DA in the VP has to be considered as a substantial modulator. Dysregulation of the mesopallidal DA neurons, as well as their glutamatergic control, may play an additional or distinct role in disorders like schizophrenia and drug addiction.
Defensins are dominant HLA-DR-associated self-peptides from CD34− peripheral blood mononuclear cells of different tumor patients (plasmacytoma, chronic myeloid leukemia)
2000-05-01

The HLA-DR-associated peptides from peripheral blood mononuclear cells of 2 patients with plasmacytoma and 1 with chronic myeloid leukemia were isolated, identified, and compared. Several were identified as derivatives of the defensin family. Defensins (or human neutrophil peptides [HNP]) are antimicrobial, cationic peptides of 29 to 35 amino acids in length and are the major constituents of the azurophilic granules of human neutrophils. Using peripheral blood cells from leukapheresis, containing about 90% of polymorphonuclear cells, we could identify HNP-1, -2, and -4 and propeptides of up to 49 amino acids in length, eluted from HLA class II molecules. Binding of isolated and synthetic defensin peptides to various HLA-DR alleles using an in vitro binding/competition assay based on size exclusion chromatography revealed that defensin may bind into the peptide-binding groove. In a T-cell competition assay, defensins were able to reduce the proliferation of an HLA-DR-restricted T-cell line after preincubation of stimulating cells (CHO-DRB1*0401 transfectants) with defensin. Therefore, binding of defensins might prevent T-cell recognition of HLA class II molecules expressed on different blood precursor cells (all of which are “nonprofessional” antigen-presenting cells) by blocking the HLA peptide-binding groove or, alternatively, might protect defensin-expressing cells from self-destruction.
Fat- and Water-Selective MR Cine Imaging of the Human Heart
2000-05-01

Right ventricular areas with fibrosis and fatty degeneration often show normal signal intensity in standard T1-weighted images but can be differentiated from normal tissue by the new chemical shift-selective breath-hold cine techniques.
Voltage-induced release of nucleic acids from palaeontological samples
2000-05-01

Most of the protocols for the recovery of ancient DNA from palaeontological specimens are time-consuming and tend to yield inconsistent polymerase chain reaction (PCR) results. "Voltage-induced release" is a novel and rapid approach for the extraction of ancient DNA. Nucleic acids are directly electrophoresed out of powder derived from hard and soft tissues. This technique is much faster than other methods in which pulverized tissue conventionally undergoes time-consuming crude lysis steps. The total preparation time is 5-6 h. The reliability of the voltage-induced release method was validated by (i) measuring the ratio of D-to L-enantiomers of the amino acids aspartic acid, alanine, and leucine, and (ii) by specific PCR amplification of four single-copy markers of human chromosome 17 and 18. We compare voltage-induced release to a frequently used silica-based protocol. DNA extracted employing voltage-induced release was more effective in PCR amplifications, which may be attributed to the effective removal of PCR inhibitors.
Transition radiation of moving Abrikosov vortices
2000-05-01

We predict that Abrikosov vortices moving towards the surface of a superconductor emit electromagnetic radiation into free space. Passage of a single vortex line traveling at constant speed from a superconducting half space, towards the vacuum half space, is discussed in detail. The frequency distribution of the radiated intensity displays a pronounced maximum at microwave frequencies around where is the magnetic penetration depth. Coherent motion of a lattice of flux lines leads to constructive interference and increases the strength of the radiated power per vortex line by a large factor. Also the radiation source may be used to measure the velocity of Abrikosov vortices and to determine the magnetic penetration depth.
The Promoter for Constitutive Expression of the Human ICln Gene CLNS1A
2000-05-01

The ICln protein is expressed ubiquitously in mammals. Experiments designed to knock down the ICln protein in NIH 3T3 fibroblasts as well as in epithelial cells led to the conclusion that this protein is crucially involved in volume regulation after cytoplasmic swelling. Reconstitution of the ICln protein in lipid bilayers revealed the ion channel nature of ICln. Here we describe a new human promoter sequence, composed of 89 nucleotides, which is responsible for a highly constitutive expression of the ICln protein. The promoter sequence lacks a TATA box, and the transcription can be effected at multiple sites. In addition to the starting sites, upstream sequence elements are mandatory for an efficient transcription of the ICln gene (CLNS1A). These new nucleotide elements were defined by site-directed mutagenesis.
Inclusion of Copper(I) into a Novel Bipyridine-Containing Tetraphosphadiplatinacyclophane
2000-05-01

The 5,5′-bis(hydroxyalkyl)-2,2′-bipyridines 4a–c (Scheme 1) were prepared either in one step (4b, 4c) or in four steps (4a) starting with 5,5′-dimethyl-2,2′-bipyridine in each case. Reaction of 4a–c with mesyl chloride afforded the bis(mesylates) [–C5H3N–(CH2)n–CH2–OSO2Me]2 5a–c [n = 1 (a), 2 (b), 3 (c)], which could easily be transformed into the diphosphanes 6a–c by reaction with LiPPh2. Treatment of 6c, 6b with Cl2Pt(NCPh)2 and (RC6H4)2Pt(COD) according to the high-dilution method resulted in the formation of the tetraphosphadiplatinacyclophanes [–C5H3N–(CH2)4–PPh2PtCl2PPh2–(CH2)4–C5H3N–]2 (7c) and [–C5H3N–(CH2)3–PPh2Pt(C6H4R)2PPh2–(CH2)3–C5H3N–]2 (8b, 9b) (8b: R = H, 9b: R = tBu), respectively (Scheme 2). The molecular structures of 8b and 9b were elucidated by X-ray structural analyses. The noncoordinated bipyridine moieties in 8b were employed to encapsulate copper(I) to give the host/guest complex 10b (Scheme 3), which was investigated by FAB-MS, NMR spectroscopy, and cyclovoltammetry. 10b exhibited a quasi-reversible oxidation at E1/2 = –0.31 V and an electrodeposition-redissolution redox system at E1/2 = –0.79 V, owing to the formation of copper at the surface of the working electrode.
How To Evaluate and Compare Tagsets? A Proposal
2000-05-01

We propose a methodology which allows an evaluation of distributional qualities of a tagset and a comparison between tagsets. Evaluation of tagset is crucial since the task of tagging is often considered as one of the first tasks in language processing. The aim of tagging is to summarise as well as possible linguistic information for further processing such as syntactic parsing. The idea is to consider these further steps in order to evaluate a given tagset, and thus to measure the pertinence of the information provided by the tagset for these steps. For this purpose, a Machine Learning system, ALLiS, is used, whose goal is to learn phrase structures from bracketed corpora and to generate formal grammar which describes these structures. ALLiS learning is based on the detection of structural regularities. By this means, it can be pointed out some non-distributional behaviours of the tagset, and thus some of its weaknesses or its inadequacies. 1. Introduction A typical and familiar cas...
A Physiological Ligand of Positive Selection Is Seen with High Specificity
2000-05-01

Abstract Positive selection is a process that ensures that peripheral T cells express TCR that are restricted to self-MHC molecules. This process requires both self-MHC and self-peptides. We have recently established a TCR transgenic mouse model (C10.4 TCRtrans+) in which the transgenic TCR was selected on the nonclassical MHC class Ib molecule H2-M3 in conjunction with a physiologically occurring peptide derived from the mitochondrial NADH-dehydrogenase subunit 1 gene (9-mer peptide). Here, the specificity of positive selection of C10.4 TCRtrans+ T cells was examined using a fetal thymic organ culture system. We demonstrated that at low peptide concentrations, shortening the NADH-dehydrogenase subunit 1 gene 9-mer peptide or mutating its surface-exposed side chains severely impaired its ability to induce positive selection. We concluded that under physiological conditions positive selection of C10.4 TCRtrans+ T cells was highly specific and occurred at low epitope densities.
Contribution of trifluoperazine metabolites to the in vivo19F NMR spectrum of rat brain
2000-05-01

Fluorine-19 NMR spectra were acquired from extracts of tissues from heads of rats given the antipsychotic drug trifluoperazine (TFP). Contributions to the in vivo (19)F spectra from tissues other than brain were negligible. The in vivo (19)F resonance at -62.3 ppm from CCl(3)F consisted of 6-8 resolved resonances in vitro. Some in vitro resonances were assigned to previously identified TFP metabolites. Multiple resonances in vitro partially explain the relatively large line width seen in vivo for TFP. Unidentified metabolites were observed at about -74 to -75 ppm in a number of spectra of extracts of brain and muscle.