Mechanical disruption

G() is related to the reversible work of adhesion obtained using contact angle measurements, but in general is greater than W. This is because once an interface is formed and the adhesive solidifies, strain energy is required to mechanically disrupt the interface. This strain energy arises because of the physical connection between the attachment sites between the adhesive and the substrate and the connectivity between this interface and the adhesive bulk. 

The high active tension and/or high active strain that occurs in muscle during lengthening contractions is believed to cause mechanical disruption of muscle fibers and connective tissue (Armstrong, 1984 Lieber and Friden, 1993). Activa-... 

These two methods produce different release profiles in vitro. Figure 5 demonstrates the release kinetics of BCNU from wafers loaded with 2.5% BCNU pressed from materials produced using these two methods. The wafers containing tritiated BCNU were placed into beakers containing 200-ml aliquots of 0.1 M phosphate buffer, pH 7.4, which were placed in a shaking water bath maintained at 37 C. The shaking rate was 20 cycles/min to avoid mechanical disruption of the wafers. The supernatant fluid was sampled periodically, and the BCNU released was determined by liquid scintillation spectrometry. The BCNU was completely released from the wafers prepared by the trituration method within the first 72 hr, whereas it took just about twice as long for the BCNU to be released from wafers... 

Sphaeroplasts were prepared by slight modifications to published methods [12,13]. Lysis of sphaeroplasts was effected by a combination of osmotic lysis and gentle mechanical disruption [14]. Discontinuous sucrose-density gradients were constructed and fractions were then assayed for protein, PG and marker enzymes for different organelles. 

Anand H, Balasundaram B, Pandit AB, Harrison STL (2007) The effect of chemical pretreatment combined with mechanical disruption on the extent of disruption and release of intracellular protein from E. coli. Biochem Eng J 35 166-173... 

The absorption efficiency of the different carotenoids is variable. For example, (3-cryptoxanthin has been reported to have higher absorption efficiency than a-cryptoxanthin in rats (Breithaupt and others 2007). Carotenoids must be liberated from the food before they can be absorbed by intestinal cells (Faulks and Southon 2005). Mechanical disruption of the food by mastication, ingestion, and mixing leads to carotenoid liberation (Guyton and Hall 2001). The enzymatic and acid-mediated hydrolysis of carbohydrates, lipids, and proteins (chemical breaking of the food) also contributes to carotenoids liberation from the food matrix (Faulks and Southon 2005). Once released, carotenoids must be dissolved in oil droplets, which are emulsified with the aqueous components of the chyme. When these oil droplets are mixed with bile in the small intestine, their size is reduced, facilitating the hydrolytic processing of lipids by the pancreatic enzymes (Pasquier and others 1996 Furr and Clark 1997 ... 

With the more conductive liquids, the ion concentration becomes so great that ion concentration fluctuations on a statistical basis are likely to be small. However, charging can take place by three other mechanisms (1) mechanical disruption of any double layer of ions that may exist at the surface in times that are short compared with the relaxation time, with a predominance of the surface ions going to the portion of fluid coming from the surface (2) unequal ion mobility with the larger ions unable to return to the bulk of liquid as readily as the smaller and more mobile ones and (3) contaminating materials, such as dust or surfactants at the interfaces serving as ion carriers into one portion or the other of the ruptured liquid. 

The amount of total enzymatic activity that becomes manifest only after disruption of membranous barriers between enzyme and substrate or upon removal of some otherwise inhibitory factor. Membrane disruption is often achieved by treatment with detergent to solubihze the enzyme. One example is the so-called microsomal glucose-6-phosphatase, an enzymatic activity that is located in the lumen of the endoplasmic reticulum but becomes trapped as a latent activity in microsome vesicles upon mechanical disruption of cells. 

Mechanical disruption methods include sonica-tion, high-speed homogenization using a French press, and bead milling, which is especially suitable... 

Removal of the debris produced by mechanical disruption can be improved if the particle diameter is increased. This can be done either by flocculation, coagulation or by binding to the various chemical bioprocessing aids such as polyvinylpyrrlidone, Whatman CDR (cell debris remover), chitosan or Biocryl bioprocessing aids (BPAS). The adsorbed materials can be removed by filtration or centrifugation. 

It is known that mechanical disruption through milling or ultrasonic treatment occurs under creation of radicals located on the ruptured ends of the broken chemical bonds. 

This observation has been used by Kargin, and Plate (127) who initiated polymerization and grafting with the help of mechanically disrupted inorganic materials. Many metals, oxides, and salts which never normally act as initiators, when mechanically disrupted, are able to initiate polymerization of styrene, methyl methacrylate, acrylonitrile, and other vinyl monomers. The surface of the active inorganic substance can also be used as a site for grafting to already existing polymer chains if joint dispersion of polymer and monomer, such as cellulose and styrene, is performed. 

The contact ends of printed circuit boards are copper. Alloys of nickel and iron are used as substrates in hermetic connectors in which glass (qv) is the dielectric material. Terminals are fabricated from brass or copper from nickel, for high temperature applications from aluminum, when aluminum conductors are used and from steel when high strength is required. Because steel has poor corrosion resistance, it is always plated using a protective metal, such as tin (see Tin AND TIN. alloys). Other substrates can be unplated when high contact normal forces, usually more than 5 N, are available to mechanically disrupt insulating oxide films on the surfaces and thereby assure metallic contact (see Corrosion and corrosion control). 

Physical Methods Physical methods include mechanical disruption by milling, homogenization, or ultrasonication. Typical high-speed bead mills are composed of a grinding chamber filled with glass or steel beads which are agitated with disks or impellers mounted on a motor-driven shaft. The efficiency of cell disruption in a bead mill depends on the concentration of the cells, the amount and size of beads, and the type and rotation speed of the agitator. The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between 30 percent to 60 percent by volume. The amount of beads in the chamber is 70 percent to 90 percent by... 

Fokkema, I.F., den Dunnen, J.T., and Taschner, P.E., 2005, LOVD easy creation of a locus-specific sequence variation database using an LSDB-in-a-box approach, Hum.Mutat., 26, 63-68 Fougerousse, F., Gonin, P., Durand, M., Richard, I. and Raymackers, J.M., 2003, Force impairment in calpain 3-deficient mice is not correlated with mechanical disruption, Muscle Nerve, 27, 616-623... 

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