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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 31 (1990), S. 851-862 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: A theoretical framework for quantization, defined by the normalized positive-definite probability operator establishing dynamical correspondence between classical and quantum Poisson brackets, is presented. The resulting quantum theory, unlike the conventional one, admits consistent probabilistic interpretation. It is shown that, in the nonrelativistic case, quantization based on the probability operator leads to the theory known as "quantum mechanics with a non-negative quantum distribution function.'' A generalization of the proposed framework to the case of the relativistic theory of fields is attempted. Four auxiliary problems of constructing probability operators of one-dimensional field oscillators in Bose and Fermi algebras are formulated and solved. On the basis of these solutions it is concluded that spinor fields are not quantizable in the Bose algebra with the help of the probability operator (the analog of Pauli's theorem). An equation for the probability operator of a system of free fields is derived from the principles of dynamical correspondence and translational invariance. The physical meaning of the operators corresponding to classical field amplitudes, such as annihilation and creation operators of field quanta with definite energy-momentum, is shown to emerge as a consequence of this equation. It is shown that the quantization of a system consisting only of tensor fields or only of spinor fields in the formalism of the probability operator leads to difficulties. It is shown further that these difficulties can be removed by considering quantization of a system containing both tensor and spinor fields. As an illustration, quantization of a system consisting of a massive vector field and a massive spinor field is considered and it is found that a noncontradictory quantization requires the mass of the vector particle to be less than that of the spinor particle. The probability operator thus acts as a mechanism of selection of the fields to be quantized already at the level of free fields.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Angiogenesis has an essential role in many important pathological and physiological settings. It has been shown that vascular permeability factor/vascular endothelial growth factor (VPF/VEGF), a potent cytokine expressed by most malignant tumors, has critical roles in vasculogenesis and both ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archiv der Mathematik 28 (1977), S. 209-216 
    ISSN: 1420-8938
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-2813
    Keywords: stomach ; carcinoma ; NF-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 55-year old man with von Recklinghausen's disease was admitted to our hospital for investigation of weight loss, anorexia, and abdominal discomfort. Endoscopy findings revealed impairment in the extendibility of the stomach by air, and barium meal studies showed a well-contracted stomach. On exploratory laparotomy, the whole of the stomach was found to be grossly shrunken with thickening of the walls suggesting a “linitis plastica” stomach. Histological findings confirmed stage III poorly differentiated diffuse infiltrative adenocarcinoma of the stomach. This report describes a rare case of “linitis plastica” stomach in a patient with peripheral neurofibromatosis (NF-1) indicating that the NF-1 disorder does not spare an individual from other common neoplastic disorders.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Annals of the Institute of Statistical Mathematics 47 (1995), S. 483-491 
    ISSN: 1572-9052
    Keywords: Non-monotonic aging ; NWBUE ; IDMRL ; BFR life distributions ; change points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The problem of estimating change points in various non-monotonic aging models is considered. A general methodology for consistent estimation of the change point is developed and applied to non-monotonic aging models based on the hazard rate function as well as on the mean residual life function.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-904X
    Keywords: cultured corneal epithelial cells ; air-interface ; paracellular permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To identify the growth conditions that would favor thedevelopment of a functional primary culture of pigmented rabbit cornealepithelial cells on a permeable support comparable to the intact tissuein bioelectric properties. Methods. Rabbit corneal epithelial cells were isolated and cultured onprecoated fibronectin/collagen/laminin permeable filters. Cells weregrown at an air-interface with supplemented DMEM/F12 medium.Immunofluorescence and electron microscopy techniques, respectively,were used to confirm cornea-specific marker and morphologicalfeatures. Permeability of the cell layers to model polar compounds wasevaluated using 14C-mannitol, fluorescein isothiocyanate (FITC) andfluorescein isothiocyanate-dextran of 4,000 molecular weight (FD4). Results. We found that culturing the epithelial cells at anair-interface (AIC) was a critical factor in the formation of tight cell layer and thatomitting fetal bovine serum and keeping the concentration of epidermalgrowth factor at 1 ng/ml were equally important. Phenotypically, theAIC cell layers were found to express cornea-specific 64 kD keratin.Compared with cells cultured under the liquid-covered (LCC)condition, those cultured under AIC exhibited a significantly higher peaktransepithelial electrical resistance (TEER) of up to 5 kωV.cm2, a higherpotential difference (PD) of up to 26 mV, and an estimated short-circuitcurrent (Ieq) of 5 μA/cm2 after 7=n8 days of culture. These values werecomparable to those in the excised cornea. Consistent with the TEER,the AIC cell layers were 4–40 times less permeable to paracellularmarkers than their LCC counterpart. Conclusions. The AIC model merits further characterization of drugtransport mechanisms as well as drug, formulation, physiological, andpathological factors influencing corneal epithelial drug transport.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-904X
    Keywords: enzyme-linked immunosorbent assay (ELISA) ; membrane ELISA ; cell ELISA ; PepT l ; dipeptide transporter ; Western blot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Boundary layer meteorology 60 (1992), S. 179-184 
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We have examined the global relation betwen the mean monthly surface level humidity and the precipitable water (Q-W relation) developed by Liu (1986) for its applicability to instantaneous data sets as proposed by Hsu and Blanchard (1989) over the Indian oceanic region. Our analysis using regional instantaneous values of W from Monex-79 in-situ data sets gave an rms error of 5.66gm/kg. This is considerably larger than the rms error of 0.4 gm/kg as obtained by Liu using the global mean monthly relation, thus failing to support Hsu and Blanchard's conjecture. However, a fifth-order polynomial in W derived by us based on instantaneous data indicates an rms error of 0.92 gm/kg.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 44 (1999), S. 916-921 
    ISSN: 1573-2568
    Keywords: DOPAMINE RECEPTOR ; MALIGNANT TUMOR ; HUMAN COLON
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract As an important enteric neurotransmitter, therole of dopamine as a mitotic inhibitor as well as aprotective factor of epithelial cells of stomach andcolon indicates its significance in malignant growth of gastrointestinal tract. Our previous resultshave shown significant alteration of dopamine receptorsin human malignant stomach tissues. The presentexperiments, therefore, evaluate DA content, itsreceptor expression, and its second-messenger cAMP inhuman malignant colon tissues to evaluate its role.Results demonstrate a significant decrease of dopaminecontent, its receptor expression, and itssecond-messenger cAMP in malignant tissues of human colon. Theseresults may provide insight into the role of dopamine asan enteric neurotransmitter on malignant growth of humancolon and may also suggest a therapeutic approach targeting dopamine receptors and itssignal transduction.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 42 (1997), S. 1260-1264 
    ISSN: 1573-2568
    Keywords: DOPAMINE RECEPTORS ; HUMAN STOMACH ; MALIGNANT GROWTH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Dopamine is an important entericneurotransmitter with a wide spectrum of physiologicalactions on the gastrointestinal tract. In addition, itshowed inhibition of malignant cell proliferation aswell as a protective influence on experimentalcarcinogenesis in the gastrointestinal tract of murinehosts. It is well established that dopamine acts ontarget cells through specific receptors. Therefore thestatus of dopamine receptors in malignant tumors ofthe stomach has been evaluated. Normal, benign, andmalignant stomach tissue showed the presence ofhigh-affinity D2 dopamine receptors. Theconcentration (Bmax) and affinity(Kd) of dopamine binding sites in normal and benigntumor tissues were similar. In malignant stomach tissueB showed a significant decrease compared to normal andbenign controls; however, Kd was similar. This alteration of dopamine receptors may be ofsignificance in d understanding the etiopathogenesis ofgastric cancer at the level of peripheralneurotransmitters. Rational use of dopamine receptorantagonists for various stomach diseases may besuggested.
    Type of Medium: Electronic Resource
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