Internal fraction

Some macromolecular probes (e g., BSA-FITC) were found to be significantly adsorbed onto the cell membrane, especially after exposure to LEF. In order to differentiate between internalized and adsorbed fractions, the cells are subjected, in the case of proteins, to 0.01% trypsin in PBS for 5 min at 37°C. The trypsin-digested BSA-FITC represents the amount of BSA adsorbed onto the cells, whereas the amount of the probe measured in the cells after trypsinization is attributed to the internalized fraction. 

The AR42J cells were plated onto 35 mm culture dishes at a final concentration of 1 X 10 cells and incubated for 1 h at 37 °C. Cells (1 x 10 cells/tube) were incubated with 1 x 10 counts/min per tube for 5, 20, 40, 80 or 120 min at 37°C. Incubation was interrupted by removal of the medium, and the cells were washed twice with PBS. After the last incubation period, 1 mL of 0.2N acetic acid/0.5M NaCl (pH2.5) was added and the cells were incubated for 5 min. The supernatant was collected (membrane bound radioligand fraction), the cells were lysed by treatment in IN NaOH, and the radioactivity associated with the cells (internalized fraction) was determined. The percentage of internalized radioactivity was calculated. At the same time, non-specific binding was evaluated by incubating cells with tracer in the presence of a high concentration of unlabelled DOTATATE (150 pL of 10 pmol in each tube). 

In another study, radiolabeled and fluorescent lipid nanocapsules were synthesized by using a phase inversion process that followed the formation of an o/w microemulsion containing triglycerides, lecithins, and a nonionic surfactant. Results of the experiment revealed that lipid nanocapsules were rapidly accumulated within cells through active and saturating mechanisms. Nanocapsules could bypass the endo-lysosomal compartment with only 10% of the cell-internalized fraction found in isolated lysosomes. When nanocapsules were loaded with paclitaxel, smallest lipid nano capsules (LNCs) also were found to trigger the best cell death activity. ... 

Within the silicate field, Parker and co-workers (Parker and Price 1989 Tschaufeser and Parker 1995) have used free energy minimization with success for modelling thermal expansion. Their approach is based on the assumption that the dominant effect of temperature is on the unit cell dimensions, rather than the internal fractional co-ordinates. If this is the case then it becomes feasible to numerically determine the strain derivatives of the free energy by finite differences as there are at most six components to evaluate and for many materials, with symmetry taken into account, there may be considerably less than this. 

Socially and culturally, the border region has been synonymous, from the mid-1960s onwards, with societal schisms (Greer Murray, 2003 3) that are not only represented by the segregation of space and symbolic forces (Shirlow, 2008), but also by a nationalist versus unionist debate, which in turn is further characterized by internal fractions within both unionism and nationalism (Bew Gillespie, 1999). In fact, some would argue that both jurisdictions are borne of a sectarian head... 

As discussed above, most ocean sediments have lanthanide distributions similar to those of the NASC. There is no net selective transport of certain lanthanides relative to others from the terrigenous sources to the oceans. The relative Ce deficiency in most ocean water is apparently a result of selective uptake of that element by authigenic ferromanganese nodules. The reasons for the other differences between the ocean water distribution and that of the NASC are not known. The lanthanide distributions for ocean water and authigenic materials demonstrate clearly that internal fractionation of the lanthanide group does occur in the oceanic environment. The concentrations of the lanthanides in ocean water are so low, however, that no large reservoir of material with a lanthanide distribution complementary to that of ocean water is to be expected. As Wildeman and Haskin (1965) indicated, the total amount of lanthanides in ocean water is less than the amount present in the upper 0.2 mm of ocean floor sediment. Thus, preferential extraction of some lanthanides from a few millimeters of sediment would not measurably alter the distribution in that sediment. 

Because of their diversity and complexity as well as the gradual internationalization of the different standards, it has proven necessary to standardize the methods of sample preservation, handling, fractionation, and analysis throughout the chain of separation and treatment. All these stages are the object of precise protocols established by official national and international organizations. They describe in as minute detail as possible the procedures employed not only for each analysis but very often giving different procedures for the same analysis in different matrices. These are the standards or standardized methods discussed in Chapter 7. 

As seen in Chapter 2, mixtures of hydrocarbons and petroleum fractions are analyzed in the laboratory using precise standards published by ASTM (American Society for Testing and Materials) and incorporated for the most part into international (ISO), European (EN) and national (NF) collections. We wiil recall below the methods utilizing a classification by boiling point ... 

In Equation (5.58) the outer summation is over the p points q which are used to sample the Brillouin zone, is the fractional weight associated with each point (related to the volume of Brillouin zone space surrounding q) and vi are the phonon frequencies. In addition to the internal energy due to the vibrational modes it is also possible to calculate the vibrational entropy, and hence the free energy. The Helmholtz free energy at a temperature... 

In a 250 ml. separatory funnel place 25 g. of anhydrous feri.-butyl alcohol (b.p. 82-83°, m.p. 25°) (1) and 85 ml. of concentrated hydrochloric acid (2) and shake the mixture from time to time during 20 minutes. After each shaking, loosen the stopper to relieve any internal pressure. Allow the mixture to stand for a few minutes until the layers have separated sharply draw off and discard the lower acid layer. Wash the halide with 20 ml. of 5 per cent, sodium bicarbonate solution and then with 20 ml. of water. Dry the preparation with 5 g. of anhydrous calcium chloride or anhydrous calcium, sulphate. Decant the dried liquid through a funnel supporting a fluted Alter paper or a small plug of cotton wool into a 100 ml. distilling flask, add 2-3 chips of porous porcelain, and distil. Collect the fraction boiling at 49-51°. The yield of feri.-butyl chloride is 28 g. 

When possible, quantitative analyses are best conducted using external standards. Emission intensity, however, is affected significantly by many parameters, including the temperature of the excitation source and the efficiency of atomization. An increase in temperature of 10 K, for example, results in a 4% change in the fraction of Na atoms present in the 3p excited state. The method of internal standards can be used when variations in source parameters are difficult to control. In this case an internal standard is selected that has an emission line close to that of the analyte to compensate for changes in the temperature of the excitation source. In addition, the internal standard should be subject to the same chemical interferences to compensate for changes in atomization efficiency. To accurately compensate for these errors, the analyte and internal standard emission lines must be monitored simultaneously. The method of standard additions also can be used. 

Figure 9.14 Calibration curve for GPC as log M versus the retention volume Vj, showing how the location of the detector signal can be used to evaluate M. Also shown are the void volume Vy and the internal volume Vj in relation to Vj, and KVj as a fraction of Vj.

Progressively smaller molecules have access to successively larger fractions of the internal volume. Therefore, as Vj emerges, consecutive fractions of the polymer come with it. Thus we can write the retention volume for a particular molecule weight fraction as... 

Efficiency. Efficiency of a device can be reported in terms of an internal quantum efficiency (photons generated/electrons injected). The external quantum efficiency often reported is lower, since this counts only those photons that escape the device. Typically only a fraction of photons escape, due to refraction and waveguiding of light at the glass interface (65). The external efficiency can be increased through the use of shaped substrates (60). 

Shell Higher Olefin Process) plant (16,17). C -C alcohols are also produced by this process. Ethylene is first oligomerized to linear, even carbon—number alpha olefins using a nickel complex catalyst. After separation of portions of the a-olefins for sale, others, particularly C g and higher, are catalyticaHy isomerized to internal olefins, which are then disproportionated over a catalyst to a broad mixture of linear internal olefins. The desired fraction is... 

In the case of a packed column, the terms on the right-hand side should each be divided by the voidage, ie, the volume fraction not occupied by the soHd packing (71). In unpacked columns at low values of the sHp velocity approximates the terminal velocity of an isolated drop, but the sHp velocity decreases with holdup and may also be affected by column internals such as agitators, baffle plates, etc. The sHp velocity can generally be represented by (73) ... 

Foams have a wide variety of appHcations that exploit their different physical properties. The low density, or high volume fraction of gas, enable foams to float on top of other fluids and to fiU large volumes with relatively Httle fluid material. These features are of particular importance in their use for fire fighting. The very high internal surface area of foams makes them useful in many separation processes. The unique rheology of foams also results in a wide variety of uses, as a foam can behave as a soHd, while stiH being able to flow once its yield stress is exceeded. 

The two-dimensional carrier confinement in the wells formed by the conduction and valence band discontinuities changes many basic semiconductor parameters. The parameter important in the laser is the density of states in the conduction and valence bands. The density of states is gready reduced in quantum well lasers (11,12). This makes it easier to achieve population inversion and thus results in a corresponding reduction in the threshold carrier density. Indeed, quantum well lasers are characterized by threshold current densities as low as 100-150 A/cm, dramatically lower than for conventional lasers. In the quantum well lasers, carriers are confined to the wells which occupy only a small fraction of the active layer volume. The internal loss owing to absorption induced by the high carrier density is very low, as Httie as 2 cm . The output efficiency of such lasers shows almost no dependence on the cavity length, a feature usehil in the preparation of high power lasers. 

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