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  • 1
    Electronic Resource
    Electronic Resource
    A photospectrometer realized in a standard integrated circuit process (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 377-383 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A photospectrometer has been realized in a standard integrated circuit (IC) process. Only the masks, materials, and fabrication steps inherent to this IC process were used (i.e., no post processing to add mechanical or optical devices for filtering). The spectrometer was composed of a set of 18 photodetectors with independent spectral responses. The responses of these devices were weighted and summed to form outputs proportional to the input optical power in discrete wavelength bands in the region from ∼400 to ∼1100 nm. With the solution space restricted to a 60 nm band, this instrument could resolve Gaussian input spectra (σ=5 nm) with a peak-to-peak spacing of less than 15 nm. This device could easily be integrated with additional analog, digital, or wireless circuits to realize a true laboratory instrument on-a-chip. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148457
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  • 2
    Electronic Resource
    Electronic Resource
    A 32-channel preamplifier chip for the multiplicity vertex detector at PHENIX (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1684-1687 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The TGV32, a 32-channel preamplifier–multiplicity discriminator chip for the multiplicity vertex detector (MVD) at PHENIX, is a unique silicon preamplifier in that it provides both an analog output for storage in an analog memory and a weighted summed-current output for conversion to a channel multiplicity count. The architecture and test results of the chip are presented. Details about the design of the preamplifier, discriminator, and programmable digital–analog converters performance as well as the process variations are presented. The chip is fabricated in a 1.2 μm, n-well, complementary metal–oxide–semiconductor process. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149651
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  • 3
    Electronic Resource
    Electronic Resource
    Elastic strain of freely suspended single-wall carbon nanotube ropes (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3803-3805 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have induced large elastic strains in ropes of single-wall carbon nanotubes, using an atomic force microscope in lateral force mode. Freely suspended ropes were observed to deform as elastic strings with tension proportional to elongation. Ropes were elastically deformed over 〉10 cycles without showing signs of plastic deformation. The maximum strain observed, 5.8±0.9%, gives a lower bound of 45±7 GPa for the tensile strength (specifically, yield stress) of single-wall nanotube ropes. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124185
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  • 4
    Electronic Resource
    Electronic Resource
    Diffusive and segmental dynamics in polymer gel electrolytes (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 11216-11221 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dynamic light scattering data on a polymer gel electrolyte with a complex relaxation behavior is presented. The electrolyte consists of lithium perchlorate dissolved in an ethylene carbonate and propylene carbonate solution that is immobilized with poly(methyl methacrylate). We attribute the observed relaxation processes to two diffusive and one segmental relaxation processes based on the form of the time decay of the intermediate scattering function and the corresponding temperature and wave vector dependencies. The dynamic light scattering results are compared with the ionic conductivity, which reveals a close connection between the fast diffusive motion of the low molecular weight solvent within the gel and the ionic conductivity. This motion is strongly decoupled from and considerably faster than the segmental motion of the polymer matrix. The results indicate that the ionic transport occurs mainly within the low molecular weight solvent. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.480477
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  • 5
    Electronic Resource
    Electronic Resource
    Homeobox gene Nkx2.2 and specification of neuronal identity by graded Sonic hedgehog signalling (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 398 (1999), S. 622-627 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] During vertebrate development, the specification of distinct cell types is thought to be controlled by inductive signals acting at different concentration thresholds. The degree of receptor activation in response to these signals is a known determinant of cell fate, but the later steps at which ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/19315
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  • 6
    Electronic Resource
    Electronic Resource
    An algorithm for correction of distortion in stereotaxic digital subtraction angiography (1998)
    Springer
    Neuroradiology 40 (1998), S. 277-282 
    Details
    ISSN: 1432-1920
    Keywords: Key words Stereotaxic techniques ; Angiography ; digital subtraction ; Therapeutic radiology ; Image processing ; computer assisted
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An algorithm for correction of the geometrical distortion in digital subtraction angiography (DSA) images was developed. Originally invented for 3D X-ray angiography, the algorithm was implemented in a computer program designed to fulfil the specific needs of stereotaxic DSA. The algorithm is based on transformation of an image of a grid from a distorted image back into its original pattern. The same transformation is then applied pixel-by-pixel to the angiographic images, which are acquired in direct conjunction with the grid image, without moving the gantry. The algorithm was tested in phantom studies and in the clinical situation with seven patients in ten examinations. Comparisons were made between co-ordinate determinations made on conventional full-size cut film and those performed on uncorrected and corrected DSA images, using 30- and 23-cm fields of view. With our method of measurement we could not show any remaining geometric distortion in the corrected DSA images. This distortion correction can, if properly applied, be used for high-precision stereotaxic DSA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002340050585
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  • 7
    Electronic Resource
    Electronic Resource
    Delivery outcome after the use of antidepressants in early pregnancy (1999)
    Springer
    European journal of clinical pharmacology 55 (1999), S. 503-508 
    Details
    ISSN: 1432-1041
    Keywords: Key words Antidepressants ; Pregnancy ; SSRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: To investigate delivery outcome after the use of antidepressants in early pregnancy. Methods: Using an ongoing prospective recording of drug use in early pregnancy, 969 women were identified who reported the use of antidepressants: 531 used only SSRI (selective serotonin re-uptake inhibitor) drugs (mostly citalopram, 375 exposures), 423 used only other antidepressants, and 15 used both. Outcome was compared with all births in the population. Results: Women using these drugs were older and smoked more than three times as often as other women. There seemed to be an excess of high parity women. The frequency of multiple births was lower than expected, resulting from too few twin births in women who had used SSRI. Gestational duration among singletons was shorter but it did not affect infant survival and was similar after the use of SSRI or non-SSRI antidepressants, perhaps the result of uncompensated for confounding or related to the underlying disease. Infants were somewhat heavier than expected, notably after non-SSRI treatment. No increase was seen in congenital abnormalities, observable in the perinatal period. Conclusions: Based on this database, the use of antidepressants in early pregnancy does not seem to carry any significant risk for the infant that is detectable during the newborn period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050664
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  • 8
    Electronic Resource
    Electronic Resource
    Involvement of the medial geniculate body in prepulse inhibition of acoustic startle (1999)
    Springer
    Psychopharmacology 141 (1999), S. 189-196 
    Details
    ISSN: 1432-2072
    Keywords: Key words Acoustic startle response ; Prepulse inhibition ; Sensorimotor gating ; Schizophrenia ; Medial geniculate body ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prepulse inhibition of acoustic startle is the normal reduction in startle response to an intense auditory stimulus when this stimulus is immediately preceded by a weaker prestimulus. Previous studies have shown that several neuroanatomical structures and pathways in the brain are involved in the modulation of prepulse inhibition. In the present study, the functional importance of the medial geniculate body (MG) in the modulation of prepulse inhibition was investigated. To this end, in vivo brain microdialysis probes were used to infuse drugs locally into the MG of awake, freely moving rats simultaneously with startle response and prepulse inhibition measurements in the same animals. Intrageniculate infusion of the sodium channel blocker, tetrodotoxin, significantly reduced prepulse inhibition without affecting baseline startle amplitude. A similar effect was obtained after intrageniculate infusion of the GABAB receptor agonist, baclofen. In addition, intrageniculate infusion of muscimol, an agonist at the GABAA receptor complex, reduced prepulse inhibition, although this effect was obtained at a higher concentration of the drug compared to that of baclofen. These studies suggest that the MG is involved in the modulation of prepulse inhibition and that auditory signals relayed via the MG may be subjected to inhibitory control at this level, involving GABA neurotransmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050824
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  • 9
    Electronic Resource
    Electronic Resource
    The role of catecholamines in desmopressin induced locomotor stimulation (1998)
    Springer
    Journal of neural transmission 105 (1998), S. 1103-1115 
    Details
    ISSN: 1435-1463
    Keywords: Keywords: Catecholamines ; dopamine ; desmopressin ; locomotor activity ; rat.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary. Central and peripheral administration of DDAVP increase locomotor activity in rats in doses that alter brain dopamine neurochemistry. In order to delineate the role of catecholamines in this behavioural effect of DDAVP, the effects of different catecholamine manipulating agents on DDAVP-induced locomotor stimulation were studied in rats. The catecholamine depleting agent reserpine (5 mg/kg), administered alone or together with the catecholamine synthesis inhibitor α-methyltyrosine (250 mg/kg), completely prevented the locomotor stimulatory effect of DDAVP. The dopamine D1 receptor antagonist Sch-23390 (0.01 and 0.03 mg/kg) significantly antagonized the DDAVP-induced locomotor stimulation when adminis-tered in the higher dose, that also produced a significant reduction of locomotor activity per se, whereas the dopamine D2 receptor antagonist raclopride (0.08 and 0.16 mg/kg) had no significant effect. The two dopamine blockers administered together produced a significant, dose-dependent reduction of DDAVP-induced locomotor stimulation, while controls were not significantly affected. Also the α-adrenoceptor antagonist phenoxybenzamine decreased the DDAVP-induced locomotor stimulation in a dose (20 mg/kg) that did not influence locomotor activity in controls, and, finally, administration of Sch-23390, raclopride and phenoxybenzamine antagonised the DDAVP-induced effect in a dose combination that failed to influence locomotor activity per se. In vivo microdialysis experiments in awake, freely moving rats indicated that DDAVP increases dopamine overflow in the nucleus accumbens, a brain area of importance for initiation of locomotor activity, by approximately 25%, as compared to baseline levels. Taken together, these results indicate that the central stimulatory action of DDAVP involves granula-mediated dopamine release and subsequent activation of dopamine D1 and D2 receptors, and that α-adrenoceptors possibly also are involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007020050115
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  • 10
    Electronic Resource
    Electronic Resource
    Regulation of BAX and BCL‐2 expression in breast cancer cells by chemotherapy (1999)
    Springer
    Breast cancer research and treatment 55 (1999), S. 107-117 
    Details
    ISSN: 1573-7217
    Keywords: apoptosis ; Bax ; Bcl‐2 ; breast cancer ; chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Optimizing chemotherapeutic drug delivery strategies relies, in part, on identification of the most clinically effective sequence, dose, and duration of drug exposure. The combination of dose intensive etoposide (VP‐16) followed by cyclophosphamide has clinical efficacy in the treatment of advanced breast cancer. However, molecular mechanisms that underlie the effectiveness of this combination of chemotherapeutic agents have not been investigated. In this study we investigated regulation of BAX and BCL‐2 expression by VP‐16 and cyclophosphamide as a potential mechanism for the induction of breast cancer cell death induced by this regimen. There was a dose and time dependent increase in BAX expression in the breast cancer cell lines MCF‐7, MDA‐MB‐435S, and MDA‐MB‐A231 following in vitro treatment with 50–100 μM VP‐16. Elevation of BAX protein expression in the presence of VP‐16 alone did not correlate with reduced viability or induction of apoptosis in MCF‐7, MDA‐MB‐435S, or MDA‐MB‐A231. VP‐16 did effectively block the breast cancer cell lines evaluated (MCF‐7 and MDA‐MB‐435S) at G2/M phase of the cell cycle, confirming activity of the drug in vitro. MCF‐7 and MDA‐MB‐435S cells that were pre‐treated with VP‐16 and subsequently exposed to 1.0–12.0 μg/m1 4‐hydroperoxycyclophosphamide (4HC), an active metabolite of cyclophosphamide, had markedly reduced viability when compared to matched controls treated with either VP‐16 or 4HC individually. Consistent with this loss of viability, exposure of all three cell lines to the combination of VP‐16 and 4HC resulted in higher BAX protein levels than those observed following treatment with either single agent. This combination of chemotherapeutic agents also resulted in reduced BCL‐2 expression. These observations suggest that combination chemotherapy may derive its efficacy, in part, through coordinated regulation of specific gene products associated with apoptosis. Characterization of molecular events that underlie susceptibility of specific tumor cells to combination chemotherapeutic regimens may lead to additional improvements in treatment strategies for this disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006175811676
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