Depletion method

The characterization of the laser pulse widths can be done with commercial autocorrelators or by a variety of other methods that can be found in the ultrafast laser literature. " For example, we have found it convenient to find time zero delay between the pump and probe laser beams in picosecond TR experiments by using fluorescence depletion of trans-stilbene. In this method, the time zero was ascertained by varying the optical delay between the pump and probe beams to a position where the depletion of the stilbene fluorescence was halfway to the maximum fluorescence depletion by the probe laser. The accuracy of the time zero measurement was estimated to be +0.5ps for 1.5ps laser pulses. A typical cross correlation time between the pump and probe pulses can also be measured by the fluorescence depletion method. 

Adsorption is determined by the depletion method using a Dohrmann DC 80 carbon analyzer. The mineral is contacted with the polymer solution and agitated with a mechanical tumbler for 24 hours, a time which has been verified to be sufficient for adsorption to be complete (9). A more detailed description of experimental procedures is given elsewhere (10). All the data reported in this study are taken in the plateau region of the adsorption isotherm. 

QDs excited by single or multiple photons exhibit multixponen-tial decays, in our hands generally with two components of <10 and 10-25 ns. This property renders the nanoparticles useful reagents for the systematic modulation of emission via a technique we have denoted as photochromic FRET (pcFRET, Fig. 12.5 see [1, 2, 134]). The method was developed in order to circumvent inherent limitations in the quantitative determination of FRET in cells, particularly in imaging applications. We have classified pcFRET as a member of the family of so-called acceptor depletion methods [1, 2] due to the reversible change in the structure, and thus spectroscopic properties, of the photochromic compound (e.g., a diheteroarylethene) serving as the FRET acceptor. The key... 

Figure 7. A serotonergic synapse including a depiction of the acute tryptophan depletion method discussed in the text. All large neutral amino acids (SLNAAs) share a common blood-brain barrier transporter. The serotonergic precursor, tryptophan, essentially competes with the other LNAAs for transport. Thus tryptophan is uniquely susceptible to acute dietary manipulation. Numerous serotonergic receptor types exist, including presynaptic S-HTm and (somatodendritic) 5-HTia autoreceptors and postsynaptic 5-HTia, 5-HTid, 5-HT2a 5-HT2c 5-HT3 and 5-HT4 receptors. Additional modulation of serotonin activity can occur via the action of selective serotonin re-uptake inhibitors (SSRls) including fluoxetine, fluvoxamine, and citalopram.

The adsorption and the covalent grafting of DNA, RNA, and ODN onto colloidal particles have mostly been carried out using the classical depletion method (static method) generally used in the case of proteins and polymers. The ad-... 

When adsorption from solution Is monitored by the depletion method. It Is very difficult to measure changes in bulk concentration over time Intervals down to milliseconds. Perhaps this Is the reason that such systematic studies are not abundant in the literature. Fast measurements require stopped-flow, pressure-jump or temperature-jump techniques. The method used to determine concentrations must also be fast suitable methods include certain spectroscopies and, for charged substances, conductivity. When adsorption on Fresnel surfaces Is studied, say by reflectometry, concentration measurements in the solution are not needed. 

Ogata Y, Charlesworth MC, Muddiman DC (2005) Evaluation of protein depletion methods for the analysis of total-, phospho-and glycoproteins in lumhar cerebrospinal fluid. J Proteome Res 4 837-845. 

Clearly satisfactory validation of a residue depletion method would be significantly different in many respects from that demanded by a regulatory method. But who should develop the regulatory method and how is it to be decided if a method is suitable for regulatory purposes ... 

R19. Rosemberg, E., Solod, E. A., and Albert, A., Luteinising hormone activity of human pituitary gonadotropin as determined by the ventral prostate weight and the ovarian ascorbic acid depletion methods of assay. J. Clin. Endocrinol. Melab. 24, 714-728 (1964). 

Adsorption isotherms are habitually obtained using the solution depletion method, which consists of comparing the solute concentrations before and after the attainment of adsorption equilibrium. Electrokinetic or zeta potentials are determined by two techniques microelectrophoresis [12,14,17] and streaming potential [13,58,59]. The former is employed to measure the mobility of small particles of chemically pure adsorbents, whereas the latter is adopted to investigate the electrophoretic behaviour of less pure coarser mineral particles. A correlation between the adsorption and electrophoretic results is usually examined with the aim of sheding light on the mechanism by means of which the surfactants are adsorbed at the solution-solid interface. This implies the necessity of maintaining the same experimental conditions in both experiments. For this purpose, the same initial operational procedure is applied. 

Yu S, Li S, Yang H, Lee F, Wu JT, Qian MG. A novel liquid chromatography/tandem mass spectrometry based depletion method for measuring red blood cell partitioning of pharmaceutical compounds in drug discovery. Rapid Commun Mass Spectrom 2005b 19(2) 250-254. 

The Rancimat method has been used to measure the antioxidant activity of synthetic and natural antioxidants (2-/>2d) and has correlated well with oil stability measured by the Active Oxygen Method (27) and peroxide value measurement (28). Our study showed that using the Rancimat method to study the antiphotooxidative effect of carotenoids on the soybean oil was in agreement with the results using the headspace oxygen depletion method (16) and the peroxide value method (16,JT). 

Four enzymes, required for the lecithin biosynthesis are reconstituted in a soybeanPC proteoliposome. Short- and long-chain lecithin can be synthesized within such liposomes, that were prepared by the detergent depletion method. 

The isotherms of ion adsorption onto silica surfaces were determined by the depletion method and calculated from the difference between initial ion concentration and the one measured in the supernatant after 24 hours of equilibration. The isotherms of cation and anion adsorbtion r(C) (Figure 36.4) show their nonequivalent character (adsorption of cations is always greater than of anions and increases in the order Li < Na < K). 

The correlation between age and the ACTH concentration of the human pituitary wa.s studied by Taylor et al. (1953) on a limited number of samples with the use of the ascorbic acid depletion method. In preliminary qualitative assays, the presence of ACTH was demonstrated in fetal pituitary... 

Separation/characterization of net charge (dissolved proteins depletion method) Capillary electrophoresis (CE)... 

Besides direct surface analysis methods, indirect solution depletion methods can be applied to study protein adsorption. Solution depletion methods use solids of known large surface area (usually dispersed solids) that are placed into a solution of known protein concentration. After incubation, the concentration of the protein in the supernatant is measured. From the depletion, the adsorbed protein amount can be calculated. 

The above examples have all involved long-lived states leading to fluorescence from the upper excited state. In contrast, the fluorescence depletion method described above has been used to resolve shortlived levels of the E state of NO with line-widths as great as 10 cm (Ashfold et. al. 1986). In this case A - X fluorescence was excited by a two-photon transition with a blue dye laser, and e2e+ - a2e+ resonances were probed with a red dye laser. Even with these broad resonances it was possible to produce fluorescence dips of 50% - indeed care had to be taken to avoid power broadening because of the very large transition moment of the E-A inter-Rydberg transition. 

Shores KS, Knapp DR. Assessment approach for evaluating high abundance protein depletion methods for cerebrospinal fluid (CSF) proteomic analysis. J Proteome Res 2007 6(9) 3739-3751. 

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