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  • 1
    Electronic Resource
    Electronic Resource
    Vesicle propulsion in haptotaxis: A local model (2000)
    Springer
    The European physical journal 3 (2000), S. 403-412 
    Details
    ISSN: 1292-895X
    Keywords: PACS. 87.16.-b Subcellular structure and processes [:AND:] 87.19.-j Properties of higher organisms - 47.55.Dz Drops and bubbles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We study theoretically vesicle locomotion due to haptotaxis. Haptotaxis is referred to motion induced by an adhesion gradient on a substrate. The problem is solved within a local approximation where a Rayleigh-type dissipation is adopted. The dynamical model is akin to the Rousse model for polymers. An invariant formulation is used to solve a dynamical model which includes a kind of dissipation due to bond breaking/restoring with the substrate. For a stationary situation where the vesicle acquires a constant drift velocity, we formulate the propulsion problem in terms of a nonlinear eigenvalue (the a priori unknown drift velocity) one of Barenblat-Zeldovitch type. A counting argument shows that the velocity belongs to a discrete set. For a relatively tense vesicle, we provide an analytical expression for the drift velocity as a function of relevant parameters. We find good agreement with the full numerical solution. Despite the oversimplification of the model it allows the identification of a relevant quantity, namely the adhesion length, which turns out to be crucial also in the nonlocal model in the presence of hydrodynamics, a situation on which we have recently reported (I. Cantat and C. Misbah, Phys. Rev. Lett. 83, 235 (1999)) and which constitutes the subject of a forthcoming extensive study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101890070011
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  • 2
    Electronic Resource
    Electronic Resource
    Endothelial dysfunction in the klotho mouse and downregulation of klotho gene expression in various animal models of vascular and metabolic diseases (2000)
    Springer
    Cellular and molecular life sciences 57 (2000), S. 738-746 
    Details
    ISSN: 1420-9071
    Keywords: Key words.klotho; endothelial function; nitric oxide production; hypertension; renal failure; cytokine.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The human aging process is associated with vascular endothelial dysfunction. However, humoral factors which might protect against endothelial dysfucntion during aging have not yet been identified. We recently identified the klotho gene as a possible regulator of human aging. In the present study using the klotho-deficient heterozygous mouse, we examined whether the Klotho protein is a humoral factor protecting against endothelial dysfunction. We further cloned rat klotho cDNA and investigated whether klotho mRNA expression in rat kidney is altered under pathological conditions such as hypertension, hyperlipidemia, renal failure, and inflammatory stress. The Klotho protein itself, or its metabolites, promotes endothelial NO production in aorta as well as arterioles, and klotho mRNA in kidney is downregulated under sustained circulatory stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000180050038
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  • 3
    Electronic Resource
    Electronic Resource
    Expression of MyoD and myogenin in dystrophic mice, mdx and dy, during regeneration (2000)
    Springer
    Acta neuropathologica 99 (2000), S. 619-627 
    Details
    ISSN: 1432-0533
    Keywords: Key words MyoD ; Myogenin ; Muscle regeneration ; dy mouse ; mdx mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Expression of two myogenic regulatory factors, MyoD and myogenin, was studied in regenerating muscles of dystrophic mice and compared to a chemically induced regeneration process. First, the distribution of the two proteins was determined immunohistochemically at various time points after single administrations of a local anaesthetic, bupivacaine hydrochloride, which causes myonecrosis followed by regeneration. Detectable levels of MyoD appeared at 18 h and the expression reached their maximum levels at 48 h after the injection, which coincide with the stage when satellite cells are activated and start to proliferate. Myogenin became detectable in 24 h and its expression reached its highest level at 72 h after injection when newly formed myotubes appeared. The two genes were also expressed in the dystrophic muscles from dy and mdx mice which exhibit dystrophic pathological features but are associated with different phenotypes. In mdx mice the two genes were expressed at reasonably high levels in parallel with the active regenerating process, whereas in dy mice MyoD and myogenin expressions decreased as fibrosis progressed. However, MyoD was relatively more strongly expressed in the larger mature myotubes of dy mice than in those of mdx mice, suggesting prolonged regenerative activity. In dy and mdx mice, MyoD and myogenin were expressed in different quantities, indicating that these animals have distinct regenerating activities. Our findings confirm that expression of both MyoD and myogenin genes is necessary in the regenerative process for the proliferation of satellite cells (myoblasts) and for the development of early regenerating fibers (myotubes) even in dystrophic muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010051172
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  • 4
    Electronic Resource
    Electronic Resource
    The developmental and aging changes of Down’s syndrome cell adhesion molecule expression in normal and Down’s syndrome brains (2000)
    Springer
    Acta neuropathologica 100 (2000), S. 654-664 
    Details
    ISSN: 1432-0533
    Keywords: Key words Dementia ; Down’s syndrome ; Down’s ; syndrome cell adhesion molecule ; Mental retardation ; Senile plaque
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied the expression of Down’s syndrome cell adhesion molecule (DSCAM) in Down’s syndrome (DS) and control brains, using antisera against peptide fragments of DSCAM. On Western blots of human, mouse and rat brain homogenates, the antisera recognized a product at approximately 200 kDa. In the brain of a 2-year-old patient with DS, Western blotting revealed an overexpression of DSCAM compared to an age-matched control. Immunohistochemistry demonstrated DSCAM in the cerebral and cerebellar white matter of both control and DS subjects, in accordance with the temporal and spatial sequence of myelination. In DS brains, immunoreactivity for DSCAM, compared to that for controls, was enhanced in the Purkinje cells at all ages, and in the cortical neurons during adulthood. In demented DS patients, DSCAM immunoreactivity was observed in the core and periphery of senile plaques. The pattern of DSCAM expression suggests that it may play a role as an adhesion molecule regulating myelination. The overexpression of DSCAM may also play a role in the mental retardation and the precocious dementia of DS patients, although the mechanism of neuronal dysfunction is undetermined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010000230
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of pre-operative administration of midazolam on the development of intra-operative hypothermia (2004)
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 59 (2004), S. 0 
    Details
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Midazolam is often used for premedication; it is known to promote vasodilation and may therefore affect redistribution of heat during surgery. We examined the effect of pre-operative administration of midazolam on the development of intra-operative hypothermia. Forty-five patients were randomly allocated to one of three groups to receive no premedication (Group C), IM midazolam 0.04 mg.kg−1 (Group M1) or 0.08 mg.kg−1 (Group M2) 30 min prior to anaesthesia. Sedation levels were assessed, and then general anaesthesia was induced and maintained using propofol and fentanyl. During surgery, core temperature, which was similar for the three groups prior to induction of anaesthesia, decreased significantly less in the midazolam groups M1 and M2 compared to the control group C. Patients who were more heavily sedated prior to induction of anaesthesia, had significantly lower core temperatures peri-operatively than those who were less sedated, and core temperatures in unpremedicated patients fell to significantly lower levels during surgery than those who were drowsy. We conclude that pre-operative administration of midazolam produces an effect on the development of peri-operative hypothermia. We found that moderate pre-operative sedation reduces the peri-operative heat loss, possibly by affecting core-to-peripheral heat distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2044.2004.03601.x
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  • 6
    Electronic Resource
    Electronic Resource
    Double tunnel junctions for magnetic random access memory devices (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 6064-6066 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optimum junction resistance and minimum tunnel magnetoresistance (TMR) ratio required for high density and high performance magnetoresistive random access memory (MRAM) devices with a TMR cell plus field effect transistor (FET) switch architecture are discussed by taking into account the variation of FET resistance causing noise. This implies that a TMR ratio over 25% at a 400 mV bias voltage and junction resistance of several tens of kilo-ohms for TMR cells are required with a signal voltage of 30 mV and a sense current of 10 μA, which leads to about 10 ns read time. This large magnetoresistance ratio at the elevated bias voltage requires low bias voltage dependence of TMR for the MRAM devices. In order to try to meet this requirement, double tunnel junctions were fabricated which possess the central ferromagnetic layer consisting of a thin discontinuous layer of hard ferromagnetic Co80Pt20 nanoparticles and insulating Al2O3 prepared by alternate sputtering of Co80Pt20 and Al2O3 targets. The maximum TMR obtained was 20.5% at room temperature for FeCo top and bottom electrodes without annealing. Bias voltage dependence of the (NiFe/CoFe)/1.5 nm Al2O3/discontinuous CoPt/2.6 nm Al2O3/(CoFe/NiFe) double tunnel junctions were revealed to be small compared to that of single junctions, the barrier of which was also fabricated by sputtering of an Al2O3 target. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372613
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  • 7
    Electronic Resource
    Electronic Resource
    Absorption in the visible region of LiNbO3 sequentially implanted with Ag and Cu ions (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 1276-1279 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ag and Cu ions were implanted sequentially into LiNbO3 at different ratios of Cu and Ag ions, and in two different energy regimes: kiloelectron volt and megaelectron volt. Optical absorption spectra were measured in the visible region at each stage in the process of annealing the sample. For the samples implanted sequentially with Ag and Cu ions at the low energy of 20 keV, only one peak appeared between 430 and 630 nm, the position of which depended on the ratios of Ag and Cu ions. For the samples implanted at high energies of 3 or 4.2 MeV, two large and distinct absorption peaks were observed at 480 and 590 nm. When the samples were heated to high temperatures, the peak at 480 nm ascribed to colloids of Ag shifted gradually to longer wavelengths and reached 530 nm, whereas the red shift of the peak ascribed to colloids of Cu was approximately 15 nm. Cu atoms diffuse out of the doubly implanted layer faster and at lower temperatures compared with Ag, even when Cu ions were implanted deeper than the Ag. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372008
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  • 8
    Electronic Resource
    Electronic Resource
    A new type of rocket-borne neutral atom analyzer (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 3024-3030 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new-type analyzer for measurement of energetic neutral atoms (ENAs) in an energy range of 4–40 keV is described. Incoming ENAs are ionized by electron stripping at passage of an ultrathin carbon foil. After post-acceleration (by 3 kV), the particles are guided to a time-of-flight (TOF) section over a wide energy-per-charge bandwidth by means of electrostatic deflection without any potential sweeping for electrodes. Then, their velocity is measured by the TOF technique, with which species can also be identified, because the particle energies are limited to a certain range by the electrostatic deflector and acceleration upon entering the TOF section. A unique feature in the present analyzer is in the rejection method of extreme ultraviolet (EUV) contamination. In contrast to conventional usage of serrated electrodes for EUV attenuation, one of the electrostatic deflection plates is machined to be so flat that EUV photons are guided to a photon trap regardless of wavelength. The TOF device can also be used in a coincidence mode for noise suppression. The present instrument was flown on a sounding rocket, and has successfully measured ENAs precipitating into the low-latitude upper atmosphere from the magnetosphere. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1304874
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  • 9
    Electronic Resource
    Electronic Resource
    The spectrum of micronodular thymic epithelial tumours with lymphoid B-cell hyperplasia (2001)
    Oxford UK : Blackwell Science Ltd
    Histopathology 38 (2001), S. 0 
    Details
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The spectrum of micronodular thymic epithelial tumours with lymphoid B-cell hyperplasia Aims: A rare type of thymoma, micronodular thymoma with lymphoid B-cell hyperplasia, was recently reported by Suster and Moran. Thymic epithelial tumours with a similar pattern but with varied cytological features of the tumour cells are analysed. Methods and results: A total of 11 cases of thymic epithelial tumours characterized by micronodular proliferation of tumour cells separated by abundant lymphoid stroma with prominent germinal centres were reviewed clinicopathologically and examined immunohistochemically. The presence of Epstein–Barr virus (EBV) genome was also examined by in-situ hybridization. Based on the morphology of tumour epithelial cells, cases were subdivided into four groups: group 1 (two cases) having spindle epithelial cells; group 2 (two cases) showing an admixture of spindle and polygonal epithelial cells; group 3 (five cases) having polygonal epithelial cells, with mild to moderate cytological atypia in four cases, and group 4 (two cases) representing lymphoepithelioma-like carcinoma. The degree of cytological atypia and the number of tumour cells positive for MIB-1 and p53 gradually increased towards group 4. The abundant lymphoid stroma in all cases contained many CD20-positive B-cells and CD3 and CD45RO-positive T-cells. CD99-positive immature T-cells were present in all cases of groups 1 and 2 and in most cases of group 3, but not in both cases of group 4 tumours. IgG, IgM and IgD-positive plasma cells and lymphocytes were also present in all cases, more prominent in those of groups 3 and 4. The EBV genome was detected in only a few lymphocytes in five cases. Conclusions: The tumours in this series belong to a distinct category of thymic epithelial tumours and each of the above groups may constitute a spectrum in the continuum of cytological atypia. The aetiological relationship of EBV with these tumours could not be proved. The lymphoid B-cell hyperplasia may result from a host immune response and may suggest a favourable clinical course of this type of tumour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2559.2001.01133.x
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  • 10
    Electronic Resource
    Electronic Resource
    Collagenoma with pseudohypoparathyroidism (2000)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 143 (2000), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.2000.03812.x
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