Mechanical protection

Cell and Tissue Culture Laboratory Procedures in Biotechnology, edited by A. Doyle and J.B. Griffiths. 1998 John Wiley Sons Ltd. 

In microcarrier cultures, cell injury is due to the interactions (collisions) between microcarrier beads on which cells are attached, interactions between microcarriers and small turbulent eddies and interactions between microcarriers and bioreactor internals, such as the impeller and various probes (Papoutsakis, 1991a). To protect cells against injury in microcarrier bioreactors, an increased medium viscosity has been the only documented and studied medium alteration (Croughan et ai, 1989 Papoutsakis, 1991a Lakhotia Papoutsakis, 1992). Dextran (Sigma) has been used to increase the medium viscosity as discussed below. This is a purely physical mechanism of protection. 

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Mechanical Properties. Most of electronic IC devices are very fragile. They need strong mechanical protection from the encapsulant to retain their long-term reUabiUty. Encapsulant must provide mechanical protection but still maintain good temperature-cycle and thermal-shock testing, which are part of the routine reUabiUty testing of the embedding electronics. 

Where wires or conductors may pass through a metal sheet, a rubber grommet, bushing or other mechanical protection should be provided to prevent the wires from insulation damage. 

Even if the receptor by itself has high accuracy, the sensor may be unable to execute the measurement in a defined place. Quality and total accuracy depend on the combination of receptor, the converter for measured values, and mechanical protection. Mechanical protection can take the form of pockets in water and fluid and also assembly boxes which protect against pollution, humidity, and temperature in the surroundings or against electromagnetic transmissions and noise from power-supplied pipes and cables. 

Conduit systems have the advantage of offering greater mechanical protection to enclosed conductors, but they can easily lose this advantage through corrosion if not properly maintained. A conduit system which corrodes on the inside can provide false security although tlie outside appears completely sound, the system may not contain an internal explosion. Extremely rapid corrosion will occur in salt-air environments for most conduit systems of ferrous materials. In offshore environments. 

Mechanical protective equipment, such as overspeed trips. 

An open independently ventilated machine is one which is ventilated by means of a separate motor-driven blower mounted on the machine enclosure. Mechanical protection shall be as defined in 1.25.1a to 1.25.5a, inclusive. This machine is sometimes known as a blower-ventilated machine. 

Mechanical protection and cooling Open machine (with subclasses)... 

Additional roles traditionally recognised for white adipose tissue include thermal insulation (as in the blubber of sea mammals) and mechanical protection to internal organs. However, in recent years it has become apparent that the function of white adipose tissue is much more extensive. This follows from the discovery that it is a major endocrine organ, secreting a diverse... 

Protective or dermal Mechanical protection Restriction of transpiration aeration... 

Epidermal tissue of leaves Epidermal cells with and without Mechanical protection... 

Peridermal tissue of stems Cork cells and cork cambium Mechanical protection... 

Industrial fire protection and safety engineers attempt to eliminate hazards at their source or to reduce their intensity with protective systems. Hazard elimination may typically require the use of alternative and less toxic materials, changes in the process, spacing or guarding, improved ventilation or, spill control or inventory reduction measures, fire and explosion protective measures - both active and passive mechanisms, protective clothing, etc. The level or protection is dependent on the risk prevalent at the facility versus the cost to implement safety measures. 

Such sol-gel derived and ultraviolet (UV)-curable hybrids afford enhanced corrosion and mechanical protection of fibres compared to standard polymer coatings used by the fibre optics industry. These coatings are hard, transparent and impossible to strip since they become intimately bonded to the fibre surface during curing. 

Also in the PP, associated with the CM, one can find the murein sacculus (for a review see [8]). This network is formed by the macromolecule pepti-doglycan, which confers the characteristic cell shape and provides the cell with mechanical protection. Peptidoglycans are unique to prokaryotic organisms and consist of a glycan backbone of N-acetylated muramic acid and N-acetylated glucosamine and cross-linked peptide chains [9-13]. 

A one-page essay in which it is suggested that evolution in plankton is driven by a watery arms race has attracted much attention (Smetacek 2001). Smetacek discusses the concept that defence of phytoplankton by mechanical protection, increased cell size, formation of spines, or production of noxious chemicals leads to the adaptation of zooplankton to these measures. This process resulted in the shape and properties of phyto- and zooplankton that we observe today. In the years following that essay several candidate molecules were discovered and intensely studied. The concept that chemical signals and defence metabolites are important factors in plankton ecology has now become widely accepted. 

The formation of antibodies is only one mechanism by which an animal may protect itself from substances or microorganisms that are potentially harmful. A mechanical protection against infection is provided by the presence of an intact skin surface and membranes together with the secretion of mucus from many internal membrane surfaces. The acids secreted by the stomach and skin have a bactericidal effect as does the presence in many body fluids of certain enzymes, particularly lysozyme. 

The packaging must physically protect the product from the mechanical stresses of warehousing, handling and distribution. Mechanical stress may take a variety of forms, from impact through to vibration in transit and compression forces on stacking. The demands for mechanical protection will vary with product type glass ampoules will require greater protection than plastic eye drop bottles, for example. 

Figure 1 The column tube end is drawn to a fine tip. To prevent fouling the ion source with packing material a small amount of coarser HPLC material is placed inside the tip. By coating with high-temperature epoxy glue (EPO-TEK 353ND) the tip is mechanically protected. This design gives the best chromatographic results. A 30-cm packed column with 3 ym Spherisorb ODS particles gives almost 5 x 10 theoretical plates (3). The separation impedance (unretained solute time per plate multiplied by the pressure drop per plate and divided by the viscosity of the eluent) has been calculated as 750.

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