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  • 1
    Electronic Resource
    Electronic Resource
    A new method for searching for free fractional charge particles in bulk matter (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 3409-3414 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We present a new experimental method for searching for free fractional charge in bulk matter; this new method derives from the traditional Millikan liquid drop method but allows the use of much larger drops, 20–100 μm in diameter, compared to the traditional method that uses drops less than 15 μm in diameter. These larger drops provide the substantial advantage that it is then much easier to consistently generate drops containing liquid suspensions of powdered meteorites and other special minerals. These materials are of great importance in bulk searches for fractional charge particles that may have been produced in the early universe. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1308268
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  • 2
    Electronic Resource
    Electronic Resource
    Electrochemiluminescence from porous silicon in formic acid liquid-junction cells (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1468-1470 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Visible light emission from porous silicon can be stimulated by applying a positive bias to a formic acid/sodium formate liquid junction cell. The emission lasts for 45 min at +2.75 V applied potential (〈5 mA/cm2, power conversion efficiency (approximately-greater-than)10−2%) and is reliably generated from n- or p-type porous silicon. An applied voltage as low as 1.3 V is capable of generating the red (720 nm) emission, indicating that current-induced chemical reactions aid in the generation of charge carriers. A mechanism involving oxidation of formic acid followed by electron injection from a CO2− radical is proposed. Infrared spectra of the porous silicon surface taken after anodization show formation of a stable silyl-ester species that is thought to be responsible for the increase in radiative recombination efficiency through passivation of surface defects. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114497
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  • 3
    Electronic Resource
    Electronic Resource
    Electrophoresis of concentrated spherical particles with a charge-regulated surface (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 6404-6410 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The electrophoretic behavior of spherical colloidal particles is modeled theoretically. The classic analysis is extended to the case of a concentrated dispersion in which the double layer surrounding a particle can assume an arbitrary thickness, and the effect of double-layer polarization is taken into account. Also, the surface of a particle is charge regulated, which leads to a general mixed-type boundary condition, and simulates entities bearing dissociable functional groups such as biological cells and particles with a membrane layer. We show that the absolute surface potential decreases with the increase in κa, κ and a are, respectively, the reciprocal Debye length and the radius of a particle. The variation of the absolute electrophoretic mobility as a function of κa is found to have a local maximum. The higher the surface potential the more significant the effect of double-layer polarization, and it becomes insignificant if κa approaches infinity. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481203
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  • 4
    Electronic Resource
    Electronic Resource
    Sedimentation potential of a concentrated spherical colloidal suspension (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 11643-11651 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The sedimentation behavior of a concentrated suspension of charged spherical particles is investigated theoretically. The sedimentation potential is evaluated taking the effect of double layer polarization into account. A cell model is adopted to describe the present multientities system, and a pseudospectral numerical scheme is used to solve the governing electrokinetic equations, which comprise a Navior–Stokes equation for flow field and a Poisson equation for electric field. Several interesting phenomena, which are absent if double layer polarization is neglected, are observed. For example, the ratio (E*/U*), E*, and U* being, respectively, the scaled sedimentation potential and the scale velocity, has a minimum if the electrical potential is low, and has a maximum if it is high. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479103
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  • 5
    Electronic Resource
    Electronic Resource
    Meat preparation and colorectal adenomas in a large sigmoidoscopy-based case-control study in California (United States) (1997)
    Springer
    Cancer causes & control 8 (1997), S. 175-183 
    Details
    ISSN: 1573-7225
    Keywords: Adenoma ; amines ; colon ; meat-products ; mutagens ; United States
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The often observed association between red meat and colorectal cancercould be due in part to mutagens, such as heterocyclic amines (HCA), that arepresent in cooked meat. HCAs are highly mutagenic and cause intestinal tumorsin animals. The hypothesis that HCAs are also carcinogenic to humans remainsto be substantiated in epidemiologic studies. We determined the associationsof meat preparation and frequency of intake (proxy variables for HCAexposure, since HCA concentration depends on the type of meat and the way itis cooked) with the prevalence of distal colorectal adenomas in asigmoidoscopy-based case-control study of 488 matched pairs of subjects fromtwo California (United States) Kaiser Permanente Medical Centers. A more thantwofold difference in adenoma prevalence between subjects at extreme ends ofestimated HCA intake was observed. For subjects who ate red meat more thanonce per week, fried it more than 10 percent of the time, and ate it with adarkly browned surface, compared with subjects who ate red meat one time orless per week, fried it 10 or less percent of the time, and ate it with alightly browned surface, the odds ratio was 2.2 (95 percent confidenceinterval = 1.1-4.3). Adenoma prevalence also increased with frequency offrying red meat (P trend = 0.004). These results are consistent with acarcinogenic effect of HCA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018416128894
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  • 6
    Electronic Resource
    Electronic Resource
    Clinical appraisal of insulin gastric analysis (1968)
    Springer
    Digestive diseases and sciences 13 (1968), S. 21-34 
    Details
    ISSN: 1573-2568
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusion Insulin gastric analysis, properly performed and interpreted, is a reliable indicator of postoperative clinical status of patients with peptic ulcer. It can be used to assess the adequacy of vagotomy or antrectomy. Clinical experience with insulin gastric analysis confirms the findings of animal studies which indicate that cephalic secretion is essentially an integrated neurohumoral response, involving a vagal release of antral gastrin. The profound depression of basal acid in the negative-response group also indicates that basal secretion is largely under cephalic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02239208
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  • 7
    Electronic Resource
    Electronic Resource
    Stability of Alkoxycarbonylamidine Prodrugs (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 434-441 
    Details
    ISSN: 1573-904X
    Keywords: peptidomimetic stability ; alkoxycarbonylamidine ; ester ; prodrug ; pH-rate profile ; GPIIbIIIa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Alkoxycarbonylamidine prodrug modification was used to mask the positively-charged amidine moiety of an Arg-Gly-Asp pepti-domimetic and enhance oral bioavailability. The aqueous stability of ethoxycarbonylamidine (EGA), ethanethiocarbonylamidine (ETCA) and phenoxycarbonylamidine (PCA) prodrugs was examined. Methods. Degradation was followed by RP-HPLC and rate constants were determined from a degradation scheme defined by product analysis. Results. EGA gave a pH of maximum stability at pH ∼7 and was independent of pH below pH ∼4. A novel degradation pathway of EGA, conversion to ethoxycarbonyl- aminocarbonyl, was observed below pH 7. The relative rates below pH 7 were ECA~ETCA〈PCA, in the same order of decreasing pKa of the conjugate acid of the substituted amidino group. Base-catalyzed cleavage of EGA to yield the amidine derivative gave the relative rates ECA〈ETCA〈PCA, in agreement with the decreasing pKa of the leaving groups. Conclusions. The observed rate constants at all pHs were small enough that only 5-30% (depending on the substituent) undesirable degradation is predicted during transit time of the gut. The spontaneous post-absorptive conversion to the amidine drugs at neutral pH is predicted to be 6x greater for the PCA than the EGA prodrugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011928415808
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  • 8
    Electronic Resource
    Electronic Resource
    Tolbutamide gastric analysis (1968)
    Springer
    Digestive diseases and sciences 13 (1968), S. 643-655 
    Details
    ISSN: 1573-2568
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusion With rare exception, the tolbutamide gastric analysis has been shown to be a reliable indicator of clinical status in postsurgical peptic ulcer patients. In this group the side effects were rare and, when present, were very mild. Bad risk patients, considered unacceptable for an insulin gastric analysis, tolerated the entire tolbutamide test procedure without any ill effects. Only one serious reaction was observed in a patient in whom unexpected fasting hypoglycemia was overlooked. Our experience strongly suggests that tolbutamide is a useful supplementary test for evaluating the adequacy of vagotomy and/or antrectomy. In poor risk patients and the aged, the tolbutamide test is the procedure of choice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02232972
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