Dead cartridges

Pre-column HPLC Alter, ulAa-low dead volume, 0.5- im frit (Upchurch, A-318) Cartridge adapters, SPE (University Research Glass, Cat. No. URG-2440-SPECA) Stopcocks (plasAc), Luer Lock (Varian, 1213-1005)... 

Ten columns of the 24 available in a cartridge were employed to analyze all compounds in duplicate. Uracil, was employed as a dead volume marker (tO) needed for the evaluation of retention factor [k = (tr - t0)/t0]. Two additional columns were used for simultaneous analysis of the unknown. Values for the log of the capacity factor k were calculated for every compound at each percent organic content of the mobile phase log k = log [(tr - t0)/t0. For each compound, a plot of log k versus percent acetonitrile was used to calculate log k w (log k at 0% acetonitrile). 

SPEC was essentially able to market their Zr02-based ultrafiltration membranes to an already existing market in the sense that these membranes replaced polymeric UF membranes in a number of applications. They also developed a certain number of new applications. For Ceraver, the situation was different. When the Membralox membranes were first developed, microfiltration was performed exclusively with dead-end polymeric cartridge filters. In parallel to the development of inorganic MF membranes, Ceraver initiated the development of cross-flow MF with backflushing as a new industrial process. 

The analyte is dead stopped on the SPE medium by loading it onto the cartridge in a solvent of low eluting power. It may then be washed with other solvents of low eluting power and is then finally eluted with a small volume of a strong solvent. 

With an adherent cell line, initially there will be few cells in the harvest and those that are recovered may be nonviable This is not necessarily a cause for concern, since viable cells will remain attached to the fibers With a nonadherent cell line, the first 50 mL of the initial harvests may yield a higher proportion of dead cells, because these tend to fall more rapidly to the bottom of the cartridge 29. In the early stages with a nonadherent cell line, too many cells may inadvertently be removed during harvesting After centrifugation, these cells may be suspended in the replacement medium and reintroduced into the bioreactor It is also possible to use cells from a well-established bioreactor to seed another... 

Water Sorption on small dead volume Tenax cartridges, thermal desorption HRGC/MS No data No data Pankow et al 1988... 

Filtration. Filtration can include filter presses, rotary drum vacuum filters (RDVF), belt filters, and variations on synthetic membrane filtration equipment, such as filter cartridges, pancake filters, or plate and frame filter presses. These processes typically operate in a batch mode when the filter chamber is filled up or the vacuum drum cake is exhausted, a new batch must be started. This type of filtration is also called dead-end filtration because the only fluid flow is through the membrane itself. Due to the small size of cells and their compressible nature, typical cell cakes have low permeability and filter aids, such as diatomaceous earths, perlite, or other mined materials are added to overcome this limitation. Moreover, the presence of high solids and viscous polymeric fermentation byproducts can limit filtration fluxes without the use of filter aids. 

Microfilters use membranes with pores in the 0.1-1 pm range. They can filter out particles of dust, activated carbon, and ion exchange resin fines, and most microorganisms. Microfilters require low differential pressures (5-20 psi) and are available both as normal flow ( dead end ) and crossflow configurations. In pharmaceutical water purification systems, they are often used as disposable cartridge filters after activated carbon filters, softeners, and ion exchange beds. 

Some parts of a laser printer (like the EP cartridge) will be damaged if touched. Your skin produces oils and has a small surface layer of dead skin cells. These substances can collect on the delicate surface of the EP cartridge and cause malfunctions. Bottom line Keep your fingers out of where they don t belong ... 

The author expressed the view that in a long bore-hole end cartridges can be compressed to a high density ( dead pressed ) which detonate with difficulty. 

This brief overview describes some experiences using tangential-flow and dead-end ultrafiltration techniques for concentration of eukaryotic cells, proteins and virus. The data and conclusions presented here have been drawn from process development work employing available apparatus and should be considered preliminary, rather than definitive or exhaustive. Previous ultrafiltration systems have been described (1-14) for both bench and pilot scale separations of proteins and virus. This paper primarily summarizes work on cartridge and sheet filter systems and their application to processes requiring sterilizable and contained systems. 

The same cartridge filters with 2-4 sq. ft. surface area were employed in a pilot-scale production facility for semi-continuous growth of a murine lymphokine-producing cell line. This was done as dead-end filtrations, harvesting 80 to 85% of the 20-40 liter culture as cell-free filtrate and retaining 15 to 20% for inoculum to be regrown after volume restoration with fresh medium. No attempts were made to recirculate or back-flush the filter cartridges. 

Cross-flow filtration as a processing alternative for separation and concentration of soluble or dissolved components competes with traditional equipment such as dead end cartridge filtration, pre-coat filtration and centrifugation. The specific merits and weaknesses of each of these filtration alternatives are summarized in Table 3. In addition to the ability to handle wide variations in processing conditions, other considerations may need to be addressed for economical viability of cross-flow filtration. These are briefly discussed below. A more detailed discussion on process design aspects, capital and operating cost considerations is presented in Sec. 6.7. 

The largest seawater desalination plant in the World operates in Jeddah, Saudi Arabia. It has a capacity of 56,800,000 liters per day, and the TDS content of the seawater is approximately 44,000ppm. Pretreatment modules for this plant include chlorine treatment, a dual media filter, and a cartridge filter for the coagulation and filtration of dead cells of microorganisms (Figure 8). 

The same group followed up on this initial design by adding the capability for on-column sample enrichment into the sheathless interface." A small solid-phase extraction cartridge, made of RP material, was attached to the CE capillary near the point of injection. Optimization of the proper capillary diameters showed that they could achieve a mass limit of detection of 500 amol for CE-MS/MS analysis of a standard peptide using a 20-p.m i.d. capillary. This design brings to reality a true zero dead-volume sheathless CE— MS interface with the ability to preconcentrate the sample within the same capillary. 

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