Fig. 4. Effect of initial flux level on combined foulants purification. (a) FO flux versus Boc-D-FMK time. (b) Normalized flux versus filtration time. (c) Effect of initial flux level on combined foulants retention and adsorption by FO membrane. (d) Effect of initial flux level on foulant mass adsorption and foulant layer composition.Figure optionsDownload full-size imageDownload high-quality image (1338 K)Download as PowerPoint slide
3.4. Effect of cross flow velocity
Fig. 5. Effect of cross flow velocity on combined foulants purification. (a) FO flux versus filtration time. (b) Normalized flux versus filtration time. (c) Effect of cross flow velocity on combined foulants retention and adsorption by FO membrane. (d) Effect of cross flow velocity on foulant mass adsorption and foulant layer composition.Figure optionsDownload full-size imageDownload high-quality image (1065 K)Download as PowerPoint slide
It was observed that the combined foulants\’ rejection was unaffected by the cross flow velocity, reaching at or above 99.0% over the FO filtration. From Fig. 5(c), it can be seen that the obviously reduced combined foulants\’ adsorption resulted in the higher retention at the low cross flow velocity during FO filtration. Meanwhile, the tannic acid was determined to take a more dominant place in the components on the fouled membrane even at the low cross flow velocity compared to the alginate (Fig. 5(d)).
After explaining these terms again, Catherine wanted to challenge Marjorie about the relevance of her company’s strategic positioning given the ways its context had changed. She was very nervous about doing this because she thought it Boc-D-FMK could possibly be a disturbing question for Marjorie. Besides, she was not sure it was the right time to challenge Marjorie on this topic, given Marjorie’s worries about BI’s tough economic situation. At the same time, Catherine thought it would be very helpful for the future of the company if Marjorie started to reflect and work on the current and future relevance of her firm’s strategic positioning. Finally, Catherine decided to raise the question, she did Haversian canal several times – that is, in Bakhtin\’s terms, she tried to activate centripetal forces – but every time Marjorie avoided answering directly and even got slightly irritated:Come on. Relevance… For a firm, if it is not profitable and does not ensure its financial durability, I’m sorry but this means that it is wrong. For very good reasons, for bad reasons, but it does not work. So, you earn money, you continue; you don’t earn money, you disappear. That’s the way it is, that’s the rule of the game.
2. Regional setting
Bukovynka Cave is situated in the southeastern part of the Podillja–Bukovynian karst area (Ukraine), in the middle part of the Prut River valley, close to the Romania and Moldova borders (Fig. 1A). The cave is developed in the upper part of the Upper Badenian gypsum strata (N1bd2), up to 35 m thick. The gypsum deposit in this Boc-D-FMK area consists of two lithofacies. The lower lithofacies are represented by stromatolitic gypsum with intercalations of clastic gypsum, and the upper one is represented by sabre and crystalline gypsum (Peryt, 2001). The sulphate bed is underlain by few meters of sand (with 0.5–1.0 m sandstone cap) of the Lower Badenian age. The top of gypsum layer is covered with up to 1 m of Ratyn Limestone and up to 8 m of the dark-gray clay of Kosiv Formation (N1ks), with abundant algae (Lithothamnion) limestone inclusions.
Quaternary deposits include river-terrace alluvium of the Prut River, composed of so-called ‘Carpathian Pebbles’ of Early Pleistocene, and grey sand, covered with Middle- and Late Pleistocene pale-yellow loess. Due to the different erosional opening of the massif, locally the Quaternary cover is directly on top of the Ratyn Limestone. The bedding of overlying deposits is strongly dislocated by slope failures, which involve both Quaternary deposits and the upper Neogene clays.
The liver plays a major role in the metabolism of α-tocopherol. Previous studies have shown that CYP4F2 is the major CYP450 isoform involved in the metabolism of α-tocopherol (Parker et al., 2004, Sontag and Parker, 2002 and Traber, 2010). In the absence of isoform-specific data in humans, in vitro Michaelis–Menten parameter values (km and Vmax) obtained from rat microsomes were used to estimate CYP4F2-mediated metabolism of α-tocopherol in liver ( Sontag and Parker, 2002). Briefly, km was used as reported for rat; Vmax was derived based on the only relevant in vitro studies in rat ( Sontag and Parker, 2002), adjusted for microsomal protein (45 mg per gram of liver) and liver weight ( Lu et al., 2006), then allometrically scaled to humans and sheep (BW0.75). Based on the Boc-D-FMK of CYP4F2 in non-hepatic human tissues as compared to the liver ( Nishimura et al., 2003), the level of metabolism by other tissues was considered negligible, except for the kidney and GIT. For estimation of CYP4F2-mediated metabolism in the kidney and GIT, we used available human kidney and GIT CYP4F2 expression levels relative to the liver ( Nishimura et al., 2003) and then normalized to weight of the tissue for estimation of Vmax. LDL-receptor-mediated uptake of α-tocopherol into human tissue was estimated based on the observation that α-tocopherol is largely bound to lipoprotein in plasma and that LDL is the major binding plasma lipoprotein ( Behrens et al., 1982, Bjornson et al., 1976 and Davies et al., 1969). For this purpose kLDL (LDL binding rate constant) was used as reported based on available human tissue uptake experiments using 125I-labeled LDL ( Rudling et al., 1990) and Bmax LDL (maximum binding of 125I-LDL) was normalized for tissue volume. The PBPK model included differential tissue uptake, based on studies that have shown a higher uptake of radiolabeled LDL in liver, spleen, kidney and GIT ( Rudling et al., 1990). The (small) fraction of unbound α-tocopherol (fu) was estimated from a previous study on the distribution of α-tocopherol in human plasma ( Behrens et al., 1982). Emulsion cracking was mathematically described by first-order kinetics, and the cracking rate constant (kc) was estimated following IM injection of an O/W emulsion in monkeys as previously described ( Tegenge and Mitkus, 2013). The summary of estimated biochemical parameters are displayed in Table 2.