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Attached to a surface

Such lifetimes vary from less than a picosecond to times greater than the age of the universe [29]. Thus, adsorbed states with short lifetimes can occur during a surface chemical reaction, or long-lived adsorbed states exist in which atoms or molecules remain attached to a surface indefinitely. [Pg.295]

Coanda effect When a jet becomes and remains attached to a surface due to static pressure differences, as in the case of a wall jet. [Pg.1422]

Surface interactions play an important role in the ability of certain animal cells to grow and produce the desired bioproducts. An understanding of the dynamics of cell surface interactions in these "anchorage-dependent" cells (cells that function well only when attached to a surface) will be needed, for example, to improve the design of bioreactors for growing animal cells. [Pg.40]

Like enzymes, whole cells are sometime immobilized by attachment to a surface or by entrapment within a carrier material. One motivation for this is similar to the motivation for using biomass recycle in a continuous process. The cells are grown under optimal conditions for cell growth but are used at conditions optimized for transformation of substrate. A great variety of reactor types have been proposed including packed beds, fluidized and spouted beds, and air-lift reactors. A semicommercial process for beer used an air-lift reactor to achieve reaction times of 1 day compared with 5-7 days for the normal batch process. Unfortunately, the beer suffered from a mismatched flavour profile that was attributed to mass transfer limitations. [Pg.459]

In spectral identification, the first step is a comparison of the observed losses with vibrational frequencies measured by IRS in the gas phase, to see if any correlations exist. When a molecule is attached to a surface it is fettered by forces due to the chemical bonds to the surface, and there will be stretching modes of vibration... [Pg.198]

Hydrodynamic Forces Necessary To Release Non-Brownian Particles Attached to a Surface... [Pg.547]

A number of important processes depend on the permanence of particle attachment to surfaces by Van der Waal forces in the presence of flowing fluids. These include enzyme fixation, particle filtration, oil production, nuclear reaction excursions, migration of surface contaminants, etc. The release of particles attached to a surface plays an important role in these processes. [Pg.547]

Cells in vivo exist either attached to a surface or free in suspension. Adherent cell lines originate from cells of solid tissue. Breast carcinoma cell lines (such as MCF7, T47D, and SK-BR-3) are adherent cultures, and these cells are grown on the surface of plastic flasks that have been treated to facilitate adhesion (see Fig. 6.2). Suspension culture cell lines originate from cells that exist in suspension, such as those cells present in the blood and the lymphatic system (see Fig. 6.3). [Pg.104]

A change in the environment of a protein molecule, e.g. adsorption from aqueous solution onto a sorbent surface, may lead to a partial breakdown of its ordered structure, resulting in an increase of conformational entropy. This is a fundamental difference between protein adsorption and the adsorption of flexible polymers, for which attachment to a surface implies a loss of conformational entropy. [Pg.105]

In the Licari and Bailey Model [102] and also in the latest Hu and Bentley Model [105] it is proposed that the infection process be described by the Poisson distribution with mean and variance equal to a.MOI. The a-value has been proposed to be dependent on the physical system and a value of a = 0.04 was proposed for static systems [102]. For agitated systems suspension cultures Hu and Bentley proposed a value of a = 0.08 because they state that agitation systems enable higher efficiency of contact between viruses and cells [105]. This is not absolutely true, at least the true reason is not the higher mixing level but the fact that in static cultures, less cell surface is exposed to the virus, since to the cells are attached to a surface. This gives an overall constant of attachment 3-4 fold lower than in suspension systems [61]. [Pg.201]

Bubbles or drops which are prevented from moving under the influence of gravity by a flat plate are termed sessile (see Fig. 2.3a and 2.3b). When bubbles or drops remain attached to a surface with gravity acting to pull them away, they are called pendant (see Fig. 2.3c and 2.3d). Floating bubbles or drops, shown in Fig. 2.3e, are those which sit at the interface between two fluids. [Pg.22]

Amylose brushes (a layer consisting of polymer chains dangling in a solvent with one end attached to a surface is frequently referred to as a polymer brush) on spherical and planar surfaces can have several advantageous uses, such as detoxification of surfaces etc. The modification of surfaces with thin polymer films is widely used to tailor surface properties such as wettability, biocompatibility, corrosion resistance, and friction [142-144]. The advantage of polymer brushes over other surface modification methods like self-assembled monolayers is their mechanical and chemical robustness, coupled with a high degree of synthetic flexibility towards the introduction of a variety of functional groups. [Pg.34]

Burk f has laid much stress on the possibility that a molecule might be attached to a surface at more than one point, whereby a distortion, or partial separation of its atoms, is produced. Ammonia, for example, might be held to the surface of a metal by a hydrogen atom and a nitrogen atom simultaneously. Such a distortion is thought of as lowering the heat of activation and facilitating decomposition. [Pg.253]

Most animal cells only grow when attached to a surface. [Pg.103]

Attachment to a Surface wood chips, collagen, microcarriers, ion exchange resins, metal oxides... [Pg.120]

Cell immobilization methods can be divided into four major categories attachment to a surface, entrapment within a porous matrix, containment behind a barrier, and self-aggregation as summarized in Table 5.8 (Karel et al., 1985). [Pg.120]

Most of us try to keep our feet on the ground, so to speak. Fortunately, the force of gravity helps us to remain attached to the earth and keeps us from floating off into space on an endless journey through the universe and beyond. Attachment to a surface is basic to life on Earth. It is also important to an artist creating a two-dimensional work of art. The support and surface on which the artist applies materials has a major effect on the final work. [Pg.119]

Biofilms are abundant in a multitude of aquatic environments in which they cover all kinds of inorganic and organic solid surfaces. Biofilms can be defined as microorganisms attached to a surface and embedded in an extracellular gellike matrix of polymeric substances. This matrix is excreted by the microorganisms themselves and may be enriched by molecules adsorbed from the surrounding water. [Pg.285]

Repelling microbes or killing them on contact are obviously the optimal ways for an antimicrobial surface to function. However, most moist and biologically contaminated areas contain large amounts of material that nonspeciflcally attach to a surface and deactivate it fully. Furthermore, high concentrations of microbes will eventually cover any surface with dead cells, which also deactivate the surface. In the latter case, only surfaces that release biocides will retain their activity. [Pg.203]

Such oxidation-controlled molecular motion has also been used to produce molecular muscles out of [3]rotaxanes such as 108 (the wheel portion of which has been attached to a surface) which either expand or contract depending on the oxidation state (Scheme 11) <2005JA9745>. [Pg.27]

In this type of bioreactor, there is a compartment where cells remain attached to a surface or immobilized on or inside a biocompatible bed. Culture medium has to be pumped through this compartment for cells to have access to nutrients and dissolved oxygen. The main disadvantages of these bioreactors, developed for the cultivation of adherent cells that require a surface for proliferation, are the impossibility of obtaining homogeneous samples of the cell population and the limitations of scale-up. [Pg.228]


See other pages where Attached to a surface is mentioned: [Pg.442]    [Pg.475]    [Pg.299]    [Pg.391]    [Pg.231]    [Pg.2142]    [Pg.446]    [Pg.1453]    [Pg.244]    [Pg.44]    [Pg.51]    [Pg.52]    [Pg.316]    [Pg.62]    [Pg.27]    [Pg.301]    [Pg.1883]    [Pg.741]    [Pg.120]    [Pg.428]    [Pg.58]    [Pg.103]    [Pg.464]    [Pg.44]    [Pg.298]    [Pg.286]    [Pg.156]    [Pg.225]   
See also in sourсe #XX -- [ Pg.548 , Pg.549 , Pg.550 , Pg.551 , Pg.552 , Pg.553 , Pg.554 , Pg.555 , Pg.556 ]




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Surface attachment

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