Filtration studies

A horizontal belt filter has been used in place of the small dmm filter in filtration studies (17). The entire filter was placed in a large pressure vessel with no moving parts passing through the filter shell. There is no commercial filter based on this principle the utilization of the space inside the pressure vessel would be poor and the filtration areas limited. 

Figure 3 shows the final chromatogram and activity profile of purified alpha-endopsychosin. The first peak contained most of the PCP displacing activity as measured by its ability to inhibit 3H-PCP. An aliquot of the most active material was hydrolyzed in acid and the amino acid composition was determined using OPA detection. It was determined that the peptide contained approximately 26 amino acids, in close agreement with the molecular weight predicted by Sephadex gel filtration studies. N-terminal analysis revealed that the peptide was blocked at this site. The nature of this blockade is yet to be determined. Studies are under way to determine the amino acid sequence of the peptide. 

Bacterial products such as lipopolysaccharides (endotoxins) and cytokines (IL-2) are able to activate the contact system in vitro and in vivo (D9, H4, H7, M41). Immediately after severe trauma or after surgical intervention and particularly during sepsis, a reduction of plasma contact system proteins has been found (C10, K1, N9). Gel filtration studies of plasma demonstrated that plasma PK after activation becomes complexed with a2-M and Cl-Inh (W4). These complexes are rapidly eliminated from the circulation in vivo. In experimental studies in which pulmonary insufficiency was induced in dogs, a significant reduction of plasma kallikrein inhibitors was observed together with reduced HMK. Analysis of the relation be-... 

A laboratory filtration study is to be carried out at constant rate. The basic equation (Cook, 1984) comes from the relation... 

Filtration studies are conducted to investigate the filtration process (e.g., the binding of the analytes of interest to the applied filtration device, filtration discard volume, and the extraction of contaminants). 

The 2.3 A structure of the achromobacter NIR (Godden et al., 1991) has been determined from an MIR map based on native and two derivative data sets collected on an area detector. In the crystal the tightly packed arrangement of monomers around the crystallographic threefold axis suggests that the molecule must be a trimer, rather than a dimer, as originally determined from gel filtration studies. The chain tracing substantiates this. 

Fincham, A. G. Electrophoretic and sephadex gel filtration studies of bone foetal enamel matrix at acid pH. Calc. Tiss, Res. 2, 353 (1968)... 

A mixed-media filtration study on an asphalt plant effluent was also conducted. In this case, the oily waste contains a heavy fraction of asphalts. Typical influent quality to the filter was 30 to 40 ppm oil and 30 to 50... 

Baham, J., Ball, N. B., and Sposito, G. (1978). Gel filtrations studies of trace metal-fulvic acid solutions extracted from sewage sludges. J. Environ. Qual. 7,181-188. 

Burba, R, Aster, B.,Nifant eva,T.,Shkinev, V., and Spivakov, B. Y. (1998). Membrane filtration studies of aquatic humic substances and their metal species A concise overview. Part 1. Analytical fractionation by means of sequential-stage ultrafiltration. Talanta 45, 977-988. 

The conversion of 850°F+ residual SRC to lighter product was determined for several balance periods in which recoveries varied between 98.5 and 100.4 wt %. The distillations were run at a slower rate than for the filtrate studies in order to sharpen the 850°F cut point for better data reproducibility. Product distributions are shown in Figure 7. 

An interesting aspect of these simulations is that the speciation of Cu, Cd and Zn with respect to inorganic and organic ("fulvate ) ligands were qualitatively similar to what was observed in gel filtration studies (52). In these studies it was noticed that Cu was predominately bound to organics whereas Zn and Cd were observed to be predominately bound to inorganics. 

T. Alebic-Kolbah, E Kajfez, S. Rendic, V. Sunjic, A. Konowal, and G. Snatzke, Circular dichroism and gel filtration study of binding of prochirai and chiral I,4-benzodiazepin-2-ones to human serum albumin, Biochem. Pharmacol., 28 2457 (1979),... 

In order to test these hypotheses, we conducted a filtration study using a small pilot unit. This permitted us to better control back working parameters. To explore the possible release of amino acids, tbe study employed a filter partially colonized by bacteria. 

Results concerning filtration studies with 0.2 pm titanium dioxide membranes supported on stainless steel or ceramic porous tubes were recently reported by Porter et al. [47,48]. Solutions containing sodium nitrate alone and in the presence of anionic, direct and acid dyes were filtered with adjusted solution pH. Electrolyte rejections and colour rejections were measured at pH values from 4 to 10. They showed that the charged membrane was responsible for ion rejection at low ionic concentration while rejection decreased to near 0% as the salt concentration was raised to 5000 ppm. These results are consistent with long range forces associated to Debye-length which can reach several hundred Angstroms in the solution for very low ionic concentrations. 

J.J. Porter and R.S. Porter, Filtration studies of selected anionic dyes using asymmetric titanium dioxide membranes on porous stainless tubes, f. Membr. Sci., 101 (1995) 67. 

It was discovered in 1958 that anaerobically grown yeast contains a form of lactate dehydrogenase which is different from the d- and L-lac-tate cytochrome c reductases of aerobic yeast (306, 319). The enzyme has been partially purified (320, 321), and shown to contain flavin (320-322). Gel filtration studies have suggested a molecular weight of about 100,000 (320, 321). Preparations of the enzyme oxidize several d-2-hydroxyacids to the respective keto acids in a reversible manner (320). For the forward reaction, ferricyanide, 2,6-dichloroindophenol, menadione, and methylene blue have been used as electron acceptors, and for the reverse reaction leucomethyl viologen and FMNHa are effective electron donors (320). A number of L-2-hydroxyacids and 2-keto acids have been shown to be competitive inhibitors. Oxalate, cyanide, o-phenanthro-line, and EDTA are also potent inhibitors (320, 321, 323, 324). The inhibition by metal chelators develops slowly and is reversed by addition of Zn, Co, Mn +, or Fe + (320, 323-326). Substrates prevent the inhibition by chelators at concentrations considerably lower than their respective Km values (327). It has been suggested that EDTA inactivation involves the removal of a metal, most probably Zn +, from the substrate binding site of the enzyme (325, 326, 328, 329). However, others have... 

Calcium causes aggregation of hemocyanin with an increase of sedimentation coefficient from 19S at 10 5M calcium to 100S at 10 2M (209). Gel filtration study of calcium binding indicates that each mole of hemocyanin (mol. wt 50,000 daltons) binds 20 moles of calcium (209). The association constant for this binding is 75 (209). No data are available to indicate the cation specificity of binding, but it seems safe to say that one can not consider this protein to be a calcium binding protein in any strict sense. 

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