ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Springer  (43)
  • Wiley  (16)
  • American Institute of Physics (AIP)  (5)
  • American Physical Society (APS)
  • 1995-1999  (64)
  • 1
    Digitale Medien
    Digitale Medien
    Liposome-Based Optochemical Nanosensors (1999)
    Springer
    Microchimica acta 131 (1999), S. 57-64 
    Details
    ISSN: 1436-5073
    Schlagwort(e): Key words: dye-encapsulating liposomes; pH sensing; oxygen sensing; optochemical nanosensors.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract  This paper describes the optochemical pH and oxygen sensing properties of dye-encapsulating and fluorescently labeled nano-sized unilamellar liposomes. To prepare the oxygen sensitive liposomes a lipid mixture consisting of dimyristoylphospatidylcholine, cholesterol, and dihexadecyl phosphate (molar ratio 5:4:1) all dissolved in dry isopropyl alcohol is injected into a sensing dye solution. The mixture is then sonicated with a liposome maker to form dye-encapsulating liposomes. A lipid mixture consisting of dimyristoylphospatidylcholine, N-(fluorescein-5-thiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (fluorescein DHPE), cholesterol, and dihexadecyl phosphate (molar ratio 20:1:16:4) is used to prepare the pH sensitive liposomes by the same sonication technique. Fluorescein labeled DHPE phospholipids are combined with DMPC phospholipids in a 1:20 ratio to incorporate the sensing dye directly into the bilayer membrane, virtually eliminating any instability due to dye leakage. Oxygen sensing liposomes are created by encapsulating the oxygen sensitive ruthenium tris(1,10)-phenanthroline complex [Ru(phen)3]. The dye is believed to exist both in free solution within the liposome, and as an adherent on the inner membrane of the liposome. High uniformity of the liposomes is realized by extruding them back and forth through a 100 nm pore-size polycarbonate membrane. TEM images of the liposomes, stained with uranyl acetate, show that the liposomes are unilamellar, spherical in shape, maintain high structural integrity, and average 70 nm in diameter. The liposomes show high stability with respect to dye leaking at room temperature for 8 days, and high photostability when exposed to the excitation light. Individual liposomes are used to monitor the pH and oxygen level in their vicinity during the enzymatic oxidation of glucose by the enzyme glucose oxidase. The newly prepared environmentally sensitive liposomes can be applied for non-invasive pH and oxygen determination in tissues and single biological cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s006040050009
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    facet.materialart.
    Unbekannt
    Liposome-Based Optochemical Nanosensors (1999)
    Springer
    Details
    Publikationsdatum: 1999-06-24
    Print ISSN: 0026-3672
    Digitale ISSN: 1436-5073
    Thema: Chemie und Pharmazie
    Publiziert von Springer
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    AKTUELLE ARTIKEL
  • 3
    Digitale Medien
    Digitale Medien
    A new method for the synthesis of magnetoliposomes (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 5699-5701 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A new method for the synthesis of magnetoliposomes, i.e., nanosized magnetic particles coated by a phospholipid membrane, is presented. Magnetoliposomes are prepared by directly using the phospholipid vesicles as nanoreactors for the precipitation of the magnetic particles. The magnetoliposomes have been characterized using transmission electron microscopy imaging and x-ray powder diffraction. The magnetic properties of the magnetoliposomes have been investigated with a superconducting quantum interference device magnetometer. Our results indicate that the magnetoliposomes contain approximately spherical maghemite nanoparticles averaging 25 nm in diameter. The occurrence of a phospholipid bilayer surrounding the magnetic particles is confirmed both by transmission electron micrographs of samples negatively stained with uranyl acetate and by digital fluorescence imaging microscopy measurements of magnetoliposomes labeled with fluorescein. The temperature dependence of the zero field cooled and field cooled susceptibilities of the magnetoliposomes is consistent with their expected superparamagnetic nature. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.370256
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Analytical criteria for nonlinear instability of thermal structures (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 4127-4133 
    Details
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Analytical criteria for supercritical and asymptotic stability and for subcritical and superexponential instability are obtained for slab-like, spherical, and cylindrical thermal structures. It is assumed that both, the thermal conductivity κ(T) and the gain/loss function Q(T), can be written as continuous functions of the temperature and they have continuous derivatives. Conditions on κ and Q under which the symmetry of the structure determines the kind of instability (or stability) are obtained. Additionally, it is found that the response of the structure not only depends on the amplitude of the disturbance, but also on whether the disturbance increases or decreases the initial steady temperature. In particular, the threshold value for the amplitude of the disturbances beyond which a linearly stable configuration destabilizes, and explicit conditions for catastrophic heating or cooling are obtained. Applications to structures constituted by atomic and molecular gas are outlined. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.871036
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Optical gain and spontaneous emission in InGaAs/GaAs multiple quantum well laser diodes (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 582-584 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We present gain and spontaneous emission measurements in In0.35Ga0.65As/GaAs multiple quantum well lasers. First, the gain is extracted from measured amplified spontaneous emission through a laser facet. Second, unamplified spontaneous emission is detected through the transparent GaAs-substrate. Taking advantage of the fundamental relationship between gain and spontaneous emission, the separation of the electron and hole quasi-Fermi levels, ΔEF, at various bias currents below laser threshold is accurately determined. Theoretically, ΔEF is calculated utilizing a simple two-subband structure model. Fitting the theoretical predictions to the experimental data allows us to determine the threshold carrier density (nth=2.0×1018 cm−3), the in-plane hole effective mass (mv1=0.21m0), and the amount of band gap shrinkage at threshold (ΔEg,th=33 meV). © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.362721
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Carrier profile for In0.35Ga0.65As/GaAs multiquantum well lasers from capacitance–voltage measurements (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 1138-1140 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The carrier profile for MBE grown In0.35Ga0.65As/GaAs multiquantum well laser structures with nominally undoped and beryllium-doped active regions was determined by using the capacitance–voltage (C–V) technique at room temperature. A simple theoretical model was used to extract the impurity concentration and the quantum-well carrier density from the experimental profiles. We obtained a high carrier concentration in nominally undoped devices caused by a strong growth temperature dependent Be diffusion from the p-cladding layer, and no difference between doped samples with different nominal dopant location. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.115738
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Structural and carrier density dependence of carrier lifetime in InGaAs/GaAs multiple-quantum-well lasers (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 3158-3160 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The carrier lifetime in undoped and p-doped mesa and ridge waveguide In0.35Ga0.65As/GaAs multiple-quantum-well lasers is extracted from the frequency response of the spontaneous emission. The radiative recombination coefficient is found to be the same for mesa and ridge waveguide lasers, and is nearly independent of the doping level. For ridge waveguide lasers, a simple method is proposed to obtain the lateral broadening of the active region due to carrier diffusion. When the corrected active region width is considered, the threshold carrier densities for both undoped and p-doped lasers are independent of the lateral structure and cavity width. Further, the surface recombination velocity in mesa lasers is determined. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.116814
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Testing CERES-Wheat with Free-Air Carbon Dioxide Enrichment (FACE) Experiment Data: CO2 and Water Interactions (1999)
    Springer
    Semigroup forum 91 (1999), S. 247-255 
    Details
    ISSN: 1432-2137
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: 2 concentration and associated climate change on crop yields. Such model predictions are largely untested in the field, for lack of experimental data. We tested the CERES-Wheat model, modified to include leaf-level photosynthesis response to elevated CO2 using field data from 2 yr of Free-Air Carbon Dioxide Enrichment (FACE) experiments with spring wheat (Triticum aestivum L. cv. Yecora Rojo) in Maricopa, AZ. Two irrigation treatments (well-watered, WW; water-deficit stressed, WS) and two atmospheric CO2 concentrations (ambient, 350 μmol mol-1, elevated, 550 μmol mol-1) were simulated. The model was evaluated using measurements of crop phenology, aboveground dry matter (DM) production, grain yield, and evapotranspiration (ET). Model calculations of crop phenology were within 2 to 3 d of observed values under WW, ambient CO2 conditions in both years. The model did not simulate the accelerated crop phenology (5-8 d at physiological maturity) observed in the WW and elevated CO2 treatments, indicating the need to include effects of increased stomatal resistance on canopy temperature. Simulations of DM and grain yield were within 10% of measured values, except for a tendency to overcalculate DM response to CO2 by 10 to 15% in Year 1 for WS treatments. The model undercalculated cumulative ET under WW conditions by 15%; model sensitivity analyses suggest that simulation of potential evapotranspiration (PET) was too low for this arid site. The model reproduced measured dynamics of CO2-water interactions. Simulated reductions in water loss due to elevated CO2 were about 4%, in agreement with measurements. The model simulated larger increases in DM production and yield due to elevated CO2 under WS than under WW conditions. In Year 1, simulated crop response to CO2 was 2% larger (measured:3%) under WS than under WW conditions; in Year 2, it was 11% larger (measured: to be further evaluated with additional experimental datasets, is an important attribute of models used to project crop yields under elevated CO2 and climate change.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and bioavailability of a sustained-release diltiazem formulation (Mono-Tildiem LP 300 mg) after repeated administration in healthy volunteers (1995)
    Springer
    European journal of clinical pharmacology 48 (1995), S. 259-264 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Diltiazem ; sustained-release formulation ; pharmacokinetics ; bioavailability ; bioequivalence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract The usual dosage regimen of diltiazem (Tildiem) is 60 mg 3–4 times a day. A sustained-release formulation has been developed (Mono-Tildiem LP 300 mg) in order to allow a single daily administration. Two repeated dosing studies were performed in healthy volunteers. The absolute bioavailability of sustained-release diltiazem LP 300 mg was investigated using concomitant i.v. administration of 13C-labelled drug: absolute bioavailability of the “once a day” formulation was 35%. The second study compared sustained-release diltiazem LP 300 mg with the standard formulation of diltiazem. The results showed that the diltiazem plasma concentrations obtained after the LP formulation remained stable between 2 and 14 h after administration and were compatible with a once a day administration. Relative bioavailability of sustained-release diltiazem LP 300 mg was 79.3% compared with diltiazem. Therefore, a unitary dose of sustained-release diltiazem LP 300 mg was chosen as the dose equivalent to the daily dose administered with the standard diltiazem formulation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00198308
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Safety and pharmacokinetics of a single oral dose of amisulpride in healthy elderly volunteers (1998)
    Springer
    European journal of clinical pharmacology 54 (1998), S. 405-409 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Key words Amisulpride ; Elderly
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract Objective: Amisulpride is a substituted benzamide neuroleptic, which binds selectively to dopamine D2 and D3 receptors, mainly in the limbic structures. States of delusion and agitation occur frequently in the population aged more than 65 years, especially in demented patients and this sometimes requires the use of neuroleptics. The objectives of this study were to determine the safety and the pharmacokinetic profile of 50 mg of amisulpride administered orally as a single dose to elderly volunteers. Methods: Twenty healthy volunteers (10 men and 10 women) aged 65–79 years were included in this open trial. Frequent measurements of blood pressure and heart rate were made and ECG and blood samples were performed up to 72 h after drug intake. Results: The overall clinical and cardiovascular safety was satisfactory. The mean Cmax of the racemate amisulpride in elderly people was 64.1 ± 6.7 ng · ml−1, and was not different from the value of 56 ± 4.1 ng · ml−1 in young subjects. As with the Cmax, the mean values of t1/2 and AUC in elderly people (15.6 ± 1.3 h and 667 ± 51 ng · ml−1· h, respectively) were not different to values observed in young subject (respectively 11.7 ± 0.5 h and 603 ± 25 ng · ml−1· h). Conclusions: A single oral dose of amisulpride was well tolerated and showed a similar pharmacokinetic profile in healthy elderly and young subjects. However, these findings should be confirmed after multiple dosing in a larger population in order to establish the lack of need of dosage adjustment in this elderly population.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002280050483
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...