Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (5)
  • 1990-1994  (4)
  • 1960-1964
  • 1996  (5)
  • 1991  (4)
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6670-6676 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Advancement of a fine slit along a planar grain boundary in an electric field E0, applied parallel to the slit, is investigated by considering electromigration along both the grain boundary and the slit surface. Electrically induced flux in the grain boundary Igb (+ toward the slit tip) and both electrically and curvature-induced fluxes on the slit surfaces are considered assuming 2Is〉Igb, where Is is the flux (+ away from the slit tip) on each of the parallel slit surfaces far removed from the tip. Steady-state solutions of the transport equations are classified according to the value of a parameter β=tan−1 (2Is/Igb) which, under reasonable assumptions, depends on material parameters only. For 5π/4≥β≥β2, unique steady-state solutions exist; for β2〉β〉β1, multiple steady-state solutions occur; below β1≥π/4, no steady-state solution is possible. Since β1〈π/2, Igb〉0 (flux exiting the grain boundary into the slit) for all cases in which no steady-state solution is possible. In the case of multiple solutions, those corresponding to smallest width (and hence largest velocity) are determined. For all steady-state solutions, slit width and tip velocity scale as E−1/20 and E3/20, respectively. Results also apply to the propagation of a slit within a grain or along a passivation layer. Generally, tip velocities can approach 1 nm/s (3.6 μm/h), thereby representing a likely failure mechanism in fine-line (near bamboo structure) interconnects. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2354-2356 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The formation and growth of holes and hillocks at grain boundary triple junctions in thin-film conductors of gold on gallium arsenide and thin-film conductors of aluminum-1 wt. % silicon on (oxidized) silicon during the early stages of electromigration have been investigated through measurement of fractional change of electrical resistance ΔR/R and microstructural characterization by scanning and transmission electron microscopy. Each grain boundary triple junction is characterized by a unique structure factor ΔY, which defines the degree of cumulative flux divergence and, consequently, the degree of susceptibility to formation and growth of holes or hillocks. Resultant holes are characterized by a shape factor f, which defines the degree of noncircularity and, consequently, relates fractional change of hole area to ΔR/R. Estimates of the upper limit for ΔY and the average value of f are in good agreement with measured values of ΔR/R and consistent with observed microstructure.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-072X
    Keywords: Key words Phototaxis ; R-bodies ; Cysts ; Swarming ; motility ; Photopigment synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhodospirillum centenum exhibited a number of general properties typically observed in nonsulfur purple bacteria, but also displayed a number of unusual characteristics that include: (1) conversion of the vibrioid/spiral cells to thick-walled cysts under certain growth conditions; (2) absence of O2 repression of photopigment synthesis; (3) synthesis of “R-bodies”; and (4) swarming motility on agar surfaces that allows macroscopic observation of colony phototaxis. The unusual characteristics indicate that Rsp.centenum will prove to be a valuable experimental system for investigating various basic problems, especially in connection with photosensory phenomena and the regulation of photopigment synthesis by dioxygen and light. The present comparative study of 13 strains was undertaken to further define the Rsp. centenum biotype.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-2013
    Keywords: Isolated perfused kidney ; Radioimmunoassay ; Hypoxia ; Renal oxygen sensing ; cAMP ; cGMP ; Calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In this study we have investigated the role of oxygen delivery and of classic second messengers on erythropoietin production by the isolated perfused rat kidney. We found that the rat kidney was capable of de novo synthesis of erythropoietin. The erythropoietin production rate was inversely related to the oxygen pressure in the perfusate and increased from 0.17 to 1.85 U erythropoietin h−1 g kidney−1 when arterial PO2 was lowered from 500 mmHg to 30 mmHg. Addition of forskolin (10 μM) and 8-bromo-cGMP (100 μM) to the perfusate elicited significant effects on the renal vascular resistance, but had no significant effect on erythropoietin production. Hypoxia-induced erythropoietin formation, however, was blocked by calmidazolium (1 μM) and W-7 (10 μM), two structurally different putative calmodulin antagonists. Calmidazolium and W-7 had no effect on other functional parameters of the isolated perfused rat kidney such as flow rate, glomerular filtration rate or sodium reabsorption. Our findings suggest that the oxygen-sensing mechanism that controls renal erythropoietin production is primarily located in the kidney itself. A calcium/calmodulin-dependent cellular reaction could be involved in the signal transduction process.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 74 (1996), S. 51-58 
    ISSN: 1432-1440
    Keywords: Tumor necrosis factor ; Hemorrhagic shock ; Leukocyte adhesion ; Intravital microscopy ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relevance of tumor necrosis factor-α (TNF-α) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-α (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic micro-circulation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, l min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-α initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-α blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 74 (1996), S. 51-58 
    ISSN: 1432-1440
    Keywords: Key words Tumor necrosis factor ; Hemorrhagic shock ; Leukocyte adhesion ; Intravital microscopy ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The relevance of tumor necrosis factor-α (TNF-α) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-α (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic microcirculation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, 1 min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-α initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-α blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 208 (1996), S. 153-161 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The behavior of a water soluble calixarene ligand has been investigated in an (NH4)2SO4/polyethylene glycol-2000 (PEG) aqueous biphasic system. Spectroscopic measurements indicate that 4-sulfonic-calix-6-arene partitions preferentially to the polymer-rich phase in this system. The utility of this ligand as a metal ion extractant was also investigated. The addition of the calixarene (10−2M in initial PEG-rich stock solution) did not significantly enhance the partitioning of Na+, Cs+, Sr2+, Ba2+, Co2+, Cd2+, or UO 2 2+ from the (NH4)2SO4-rich to the PEG-rich phase. The partitioning behavior of these metal ions is dependent, rather, on their Gibbs free energy of hydration (ΔGhyd *).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of plastic surgery 14 (1991), S. 3-6 
    ISSN: 1435-0130
    Keywords: Skin flap ; Calcium channel blockers ; Ischemia ; Animal models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was designed to evaluate the influence of two calcium channel blockers, verapamil and nifedipine, on skin flap survival. These agents were selected because they inhibit the passage of calcium through calcium selective channels in the plasma membrane, thereby blocking calcium mediated electromechanical coupling in contractile tissue and resulting in peripheral arterial vasodilation. Three groups of pigs were used in this study. All skin flaps in this study were 3 cm wide and 12 cm long. The first group (10 flaps) served as controls with no pharmacologic manipulations. Pigs in group II (15 flaps) received verapamil (80 mg orally, three times a day) for 7 days postoperatively. Pigs in group III (15 flaps) received nifedipine (10 mg orally, three times a day) for 7 days postoperatively. Statistical analysis of the results demonstrated that both verapamil and nifedipine resulted in significant enhancement of skin flap survival. The increased survival of the skin flaps produced by nifedipine as compared to verapamil was statistically significant.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...