Retention rate

As described above, resolution can be improved by variations in plate number, selectivity or capacity factor. However, when considering the separation of a mixture which contains several components of different retention rates, the adjustment of the capacity factors has a limited influence on resolution. The retention times for the last eluted peaks can be excessive, and in some cases strongly retained sample components would not be eluted at all. 

LAAM (L-a-acetylmethadol or levomethadyl acetate) is a full agonist at the i opioid receptor with pharmacologic properties similar to those of methadone. A number of studies have demonstrated that treatment with LAAM results in reduction of opioid use and beneficial effects comparable to those achieved with methadone (Ling et al. 1978 Tennant et al. 1986 Zangwell et al. 1986). However, retention rates are higher in patients who take methadone doses of 80—100 mg/day. 

A. Skim Peel Strength Retention Rate Constant (Center), p, weeks... 

Interactions of Metal Salts with the Formation. Interactions of metal salts with the formation and distribution of the retained aluminum in a porous medium may significantly affect the location and strength of gels. This interaction was demonstrated with polyacrylamide-aluminum citrate gels [1514]. Solutions were displaced in silica sand. The major findings of this study are that as the aluminum-to-citrate ratio increases, the aluminum retention increases. Furthermore, the amount of aluminum retained by silica sand increases as the displacing rate decreases. The process is reversible, but the aluminum release rate is considerably slower than the retention rate. The amount of aluminum released is influenced by the type and the pH level of the flowing solution. The citrate ions are retained by silica sand primarily as a part of the aluminum citrate complex. Iron, cations, and some divalent cations cannot be used in the brine environment. 

A large degree of variation is apparent in retention rates for americium in the liver among various animal species (Durbin 1973), as indicated by measured or estimated liver clearance half-times of approximately 5-16 days in rats, 152 days in baboons, 1-10 years in dogs, and 10 years in Chinese hamsters. A liver clearance half-time of 2 years has been estimated for humans (Griffith et al. 1983). Refer to Section 3.5.1 for information regarding toxicokinetic mechanisms that may play a role in interspecies differences in liver retention of americium. 

Significant interspecies differences are apparent regarding liver retention rates of absorbed americium (Durbin 1973 Griffith et al. 1983) (see Sections 3.4.2.4 and 3.5.1 for more detailed information). 

Carotenoids showed good retention rates (86-100%) in minimally processed juices treated with PEF and fresh-cut vegetables treated with HHP. 

Carbamazepine and valproic acid had equal retention rates for tonic-clonic seizures, but carbamazepine was superior for partial seizures, and valproic acid caused more adverse effects. 

Crowe and Crowe [3.39] proved that it is sufficient for certain liposomes, e. g. egg phosphatidyl-choline (DPPC), to be vitrified by trehalose or dextran during freezing and freeze drying. In trehalose the retention rate was almost 100 %, and in dextran more than 80 %. This did not apply to egg PC-liposomes Dextran as CPA alone led to an almost total loss of the CF-indicator, but addition of dextran into a trehalose solution (Fig. 3.20) also reduced the retention rate of CF substantially, e. g. from 90 % in a pure trehalose to approx. 45 % if trehalose and dextran were in equal amounts in the solution. Since T of dextran is approx. -10 °C and Tg- of trehalose is -30 to -32 °C, dextran should form a glass phase at much higher temperatures than trehalose. Therefore the stabilization of egg- PC with trehalose cannot be related with the vitrification. Crowe showd with IR spectroscopy that egg-PC freeze dried with 2 g trehalose/g lipid had almost the identical spectrographic characteristics as the hydrous lipid Trehalose molecules replaced the water molecules, and hydrogen... 

Fig. 3.21. Retention rate of liposome-encapsulated hemoglobin as a function of the time elapsed after the reconstitution of the freeze dried LEH, with different trehalose concentrations as CPA. 1, no trehalose 2, 10 mM 3, 50 mM 4, 150 mM 5, 300 mM trehalose (Fig. 2 from [3.43]).

Relative retention rates (%)i) Drying at a chamber pressure (mbar)... 

This entrepreneurial culture is further evidenced by an open door policy, transparency, information-sharing within and across business units, and by a best-practices mentality. All of this leads to the industry s best retention rates of 82% for sales people and drivers, which are the key customer-facing positions. At the officer level, retention rates exceed 99% with an average tenure greater than twenty years. 

Level Retention rate (%) Average tenure (years) Average age... 

The major drawback to using an intravenous route of cell delivery would be the possibility that the therapeutic cells would become trapped in the microvasculature of the lungs, liver, and lymphoid tissues. This theoretical limitation of systemic transvenous delivery of stem cells has been confirmed experimentally. In a study by Toma et al. [97], human MSCs were injected into the left ventricular cavity of experimental mice 4 days later, an estimated 0.44% of the injected cells remained in the myocardium, and the rest had localized to the spleen, liver, and lungs. Other studies using the systemic delivery approach have produced similar results, with very low local cell retention rates of less than 5% [98, 99]. Thus, the transvenous delivery route appears unlikely to achieve the local cell concentration needed to produce a significant therapeutic benefit. 

In animals, as is the case with humans, absorption and bioavailability is influenced by age. Smith s result of Ca retention equivalence between CCM and CaCOa in older rats is different to how younger rodents responded (Smith et al., 1987). CCM in OJ was determined to be relatively better absorbed and retained than the Ca in 2% fat milk (mean SFM retention rates 51.1 1.7 vs 42.2 1.8% p <. 001), respectively. This result was reproduced when, based on extrinsic labeling, the Ca from CCM in both AJ and OJ was reported to be better absorbed in juvenile rats than was the Ca from milk (p <. 05) (Andon et al., 1996b). 

Farre M, Mas A, Torrens M, Moreno V Cami J (2002). Retention rate and illicit opioid use during methadone maintenance interventions a meta-analysis. Drug Alcohol Dependence, 65, 283-90... 

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