Millipore membranes

Experiments in 500 ml Erlenmeyer flasks and Fernbach flasks contained 200 ml and 1 L of EPl and EP2 medium respectively. Inocuia added to these cultures was 2 ml of spore suspension (5.0 optical density at 540 nm) for each 100 ml EP medium. All cultures were grown at 37°C in a shaking incubator (New Brunswik Sci. Co., USA), at 200 rpm. Then 10 ml of sample were withdrawn each 24 h during fermentation and immediately filtered through Millipore membranes of 0.45 pm pore size these cell-free filtrates were used for enzymatic assays and extracellular protein determinations by the Lowry method (14). Experiments in the 14 L fermentor (Microgen Fermentor New Brunswik Sci. Co., USA) were carried with lOL of fermentation medium EP2 and inoculum added was IL of mycelium grown 24 h in... 

The simplest system devised comprises a microcosm where seedlings with roots sandwiched between Millipore membranes are in contact with agar containing plant nutrients (25). The shoots can be exposed to CO, and the loss of C into the agar via the roots is then monitored. The design enables the effect of microorganisms on rhizodeposition to be examined easily (26) but really lacks the complexity of substratum to allow data obtained to be related to rhizodeposition in soil. 

Procedure Allelopathic aqueous leachate is prepared by soaking dried leaves (lg/100 mL or 1% w/v) in distilled water for 3 h. This leachate is filtered through Whatman paper (No. 4) and then through a sterile Millipore membrane (0.45 mm). Then, it is poured in Petri dishes and mixed with agar (2%) for a final aqueous leachate concentration of 0.5%. The volume will depend on the size of the Petri dish, 3 mL of leachate plus 3 mL of agar are enough for a 6 cm Petri dish. Osmotic potential of the leachate is measured with a freezing-point osmometer (Osmette A, Precision System Inc.). 

Both the hydrochloric acid and sodium borohydride contributed to the blank. The Sb (V) in the 12 N hydrochloric acid was removed by uptake on a Dowex 1-X8 anion exchange resin. Sodium borohydride was purified, after dissolution, by addition of 0.5 ml sodium hydroxide (50%) to 200 ml of 5% sodium borohydride, and subsequent filtration through a hydrochloric acid precleaned 0.45 pm Millipore membrane. 

Fig. 1.5.3 Aerosol generator assembly for the production of composite or coated particles (a) carrier gas (e.g., helium) tank, (b) drying column containing silica gel and molecular sieve, (c) Millipore membrane of 0.1 p.m pore size, (d) flow meters, (e) nuclei (e.g., NaCI, AgCI) generator, (f) and (m) boilers containing different reactant liquids, (g) and (n) condensation chambers, (h) heater, (i) chamber for recondensation of droplets, (q) and (e) coreactant containers, (k) and (p) vapor injection ports, (I) and (g) reaction chambers, (r) powder collector. (From Ref. 39.)...

Filter through 8-micron Millipore membrane (or equivalent). 

Reagents. Organic solvents for HPLC separations—methylene chloride, methanol, isopropyl alcohol, hexane, and acetonitrile—were obtained as HPLC grade from Fisher Scientific. Type I water for HPLC and for the preparation of other aqueous solutions was purified as described previously (7). All HPLC solvents were filtered through a 0.45-/zm Millipore membrane filter (Millipore Corporation) and degassed... 

Composite emulsion as carrier of hydrophilic medicine for chemotherapy was prepared by adding albumin to the internal water phase and lecithin or cholesterol to the oil phase, thus obtaining a water-in-oil emulsion. This emulsion was then pressed through Millipore membrane into an external water phase to form a w/o/w multiple emulsion. Its advantages are high size uniformity and high storage stability [66]. 

The quantity of EPS produced after fermentation was determined through dry weight measurements. The fermentation broth was heated at 80° 1°C for 10 min, to ensure microbial inactivation. A filtration was then conducted to remove the cells. To precipitate the EPS, ethanol P.A. (3 1) was added to the fermented broth. After total precipitation of the EPS present in the medium, the mixture (broth plus ethanol) was filtered through a 0.2-pm Millipore membrane using a Gouche crucible previously weighed. The obtained product was dried at 80 1°C until constant weight. All determinations were done in triplicate. 

The initial pH of the medium was adjusted to 7.0. All chemicals were of analytical grade. The carbon sources (commercial sugar-sucrose, sugarcane juice and molasses, sugarcane juice alcohol stillage, glycerol, mannitol, soybean oil) were added in order to establish an initial substrate concentration of 20 g/L. In some cases, the medium was also aseptically supplemented with 0.1% (w/v) yeast extract and 0.001% (w/v) Na EDTA previously and separately sterilized by filtration through a Millipore membrane with a pore size of 0.22 pm. 

The w — /o/w approach requires additional care in the setting up of two liquid-liquid interfaces. The difference from the o — /o/w procedure is that a drop of the organic phase was placed onto the Millipore membrane filter, so as to fill its pores. Any excess was wiped off with a tissue. The empty RDC is placed into the 60 cm3 of buffer, and 20 cm3 of water added to the inner compartment. Aqueous concentrate of diffusant was added to the inner compartment to initiate the experiment. 

Filtrated by Millipore membrane filter (pore size 0.45ym)... 

Rain water was collected on May 24-25, 1985 A Filtrated by Millipore membrane filter (pore size 0.45ym)... 

The sample solutions were diluted to 25ml and filtered through a 0.2uM Millipore membrane filter prior to GPC analysis. Only soluble components were analyzed by GPC. 

AL-3), and 19,000 (HSA-spacer-AL-4), The latex particles modified were purified by repeated washing with distilled water using an Amicon ultrafiltration apparatus with a Millipore membrane. 

A Waters GPC 150 CV, equipped with the DRI prototype 4 and a single capillary viscometer, was used for this study. A low-angle laser lightscattering (LALLS) detector (Chromatix CMX 100) was inserted between the column set and the GPC 150 CV detectors. Tetrahydrofuran (THF) was used at 40 °C and at a flow rate of 1 mL/mn. THF was filtered on a Millipore membrane-type FH and stabilized by lonol at a concentration of 0.04%. The columns used were a set of Waters Ultrastyragel (103—106 A). The narrow standards used for calibration were a set of polystyrene standards... 

The apparatus developed by the KIVA (the Netherlands Waterworks Testing and Research Institute) was used in this study. MFI measurements were carried out with 0.45 jUm Millipore membrane filters at a constant pressure of 200 kPa. Careful attention was paid to prevent air bubble formation in the membrane holder. For that purpose, the membrane itself was watted with demi-water before use. 

Millipore (1990) Cell Culture on Millipore Membranes A Technical Reference Guide. Millipore Corporation, Bedford, MA, USA. 

Cool down the solution to room temperature while stirring and filter with a 0.2-pm Millipore membrane. 

Dialyse overnight against PBS, filter through sterile Millipore membrane (0.22 pm). Purify and store as described in Section 11.2.2.3. ... 

Sierra Radial Slit Jet Millipore membrane mixed esters of cellulose 19.0... 

Ionic surfactants are more toxic for bacteria than nonionics [4]. Because of this fact, CTAB concentrations selected for the tests were lower than its critical micelle concentration (CMC) of 0.036% m/v. Corresponding solutions of each concentration were prepared and sterilized by vacuum filtration using a Millipore membrane of 0.45 um pore diameter. 

Figure 1. Binding stability of collagenase to Millipore membrane at 37° C. Key D, control O,...

Soluble Unoxidized Nitrogen. This form of nitrogen was determined by a Kjeldahl digestion (then distillation and nesslerization) on a sample filtered through a washed 0.45 Millipore membrane filter. Membrane filters used for separations of this type must be thoroughly washed with distilled water since it has been found that they contain soluble organic material that contributes significantly to the N content of the filtrate. 

Sheldon and Sutcliffe (17) and Sheldon (16) used a Coulter Counter to examine the particle retention of nylon and stainless-steel meshes, Whatman glassfiber filters, and Nuclepore and Millipore membranes. With light particle loading and low vacuum (12-13 cm of mercury), the Millipore and glassfiber filters retained particles of much smaller diameter than the manufacturers stated pore size. The meshes and Nuclepore membranes showed 50% retention of particles (by number) at their manufacturers reported pore sizes. 

The spontaneous crystallization temperature of each sample of treated wine (Table 1.16) was also determined using the same procedure. Examination of the results shows that a wine filtered on a 10 Da Millipore membrane, i.e. a wine from which all the colloids have been removed, has the lowest value for the supersaturation field (Tsat - Tcso), closest to that of the model dilute alcohol solution. Therefore, the difference between the results for this sample and the higher values of the supersaturation fields of fined samples define the effect of the protective colloids. It is interesting to note that the sample treated with metatartaric acid had the widest supersaturation field, and cold stabilization was completely ineffective in this case. This clearly demonstrates the inhibiting effect this polymer has on crystallization and, therefore, its stabilizing effect on wine (Section 1.7.6). Stabilization by this method, however, is not permanent. 

The solids on the filter membrane were washed with deionized distilled water three times under vacuum. Then, the solids with membrane were ttans-ferred to a 250 mL flask and an 80 mL exttactant was added into the flask. The exttactants included 0.01 M (pH 5.0) KNO3, KCl, K-cittate and K-acetate. The flasks were shaken at 20°C for 5 min to 7 days. The entire suspensions at the end of each reaction period were filtered through a 0.1-pm Millipore membrane. The Cd in the solutions was determined by the GFAAS. The experiment was carried out in duplicate. 

Nitrocellulose membrane filters MF-Millipore Membrane Filters, type HA, pore size 0.45 m, diameter 25 mm (Milli-pore, Billerica, MA). 

Reagent grade water was prepared from distilled water using a Millipore Milli-Q2 water purification system. Distilled-in-glass, UV grade tetrahydrofuran (THF) and acetonitrile (CH.CN) was used as received from Burdick Jackson Labs. Solutions were prepared in volumetric flasks and were filtered through 0.2UM Millipore membrane filters. 

In a similar study,an olive oil impregnated Millipore membrane was employed to determine the transport kinetics of several drugs between two aqueous compartments buffered at pH 1.2 and 7.4. Apparent first-order rate constants obtained for the drugs alone can be correlated with reported in vivo absorption rate constants. Each of the drugs is known to complex with caffeine, and in each case caffeine significantly reduces the rate of transport. Furthermore, calculated m vitro rate constants agree well with reported in vivo rote constants for the drug-caffeine complexes. 

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