Membrane rupture

The most developed and widely used approach to electroporation and membrane rupture views pore formation as a result of large nonlinear fluctuations, rather than loss of stability for small (linear) fluctuations. This theory of electroporation has been intensively reviewed [68-70], and we will discuss it only briefly. The approach is similar to the theory of crystal defect formation or to the phenomenology of nucleation in first-order phase transitions. The idea of applying this approach to pore formation in bimolecular free films can be traced back to the work of Deryagin and Gutop [71]. 

Organellar swelling and damage Depletion of ATP Loss of ion homeostasis Membrane rupture Nuclear lysis... 

Beyond bacteria, mammalian cells undergoing membrane rupture due to transfection with plasmid DNA have been shown to exhibit increased levels of phosphocholine by H HRMAS NMR.118 In general, this new area of research, which has been coined in-cell NMR spectroscopy, is not limited to HRMAS studies,119 but clearly there is an important role for HRMAS in the study of these heterogeneous living systems. 

Phase 1 Ions arc transported inward and crystal growth is induced within the vesicle. The intravesicular ionic product is raised resulting in the initial deposition of calcium phosphates as HA (and probably also as ACP). Eventually the vesicle membrane ruptures releasing the mineral. 

Other perturbations have been demonstrated. The pressure,, jump, similar to the T-jump in principle, is attractive for organic reactions where Joule heating may be impractical both because of the solvent being used and because concentrations might have to be measured by conductivity. Large (104—105 kPa) pressures are needed to perturb equilibrium constants. One approach involves pressurizing a liquid solution until a membrane ruptures and drops the pressure to ambient. Electric field perturbations affect some reactions and have also been used (2), but infrequendy. 

The peel, internal membranes, ruptured juice vesicles and seed residue remaining after juice extraction represent the raw material for production of dried citrus pulp. This residue, in its wet state, contains 75-85% water and ferments or sours readily because of the presence of soluble sugars. The difficulty of handling this wet material necessitates dehydration to a moisture content in the range of 107. water. Once dried, if proper precautions are taken to maintain dry conditions, the product may be handled, stored, and shipped in a manner similar to other dry feed stuffs. 

Feldmann, G., Haouzi, D., Moreau, A., Durand, S. A., Bringuier, A., Berson, A., Mansouri, A., Fau, D., and Pessayre, D., 2000, Opening of the mitochondrial permeability transition pore causes matrix expansion and outer membrane rupture in Fas-mediated hepatic apoptosis in mice, Hepatology 31, pp. 674-683... 

Doggrell SA. Recent pharmacological advances in the treatment of preterm membrane rupture, labour and delivery. Expert Opin Pharmacother. 2004 5 1917-1928. 

Fig. 18. Diagrams illustrating the differences and difficulties during freezing of cells in suspension (a) and on surfaces (b, c and d). In both cases, large ice crystal formation must be avoided, this means that freezing must be rapid and often involves the use of cryo-protectants. In suspension, the use of hypertonic solutions to shrink cells by osmosis helps to avoid membrane rupture. But with cells fixed to surfaces, shrinkage can lead to rupture of the filopodia or to parts of cytoskeleton or cell membrane (c). Additionally, animal cells under stress (including this kind of osmotic stress) tend to build up into a spherical shape. This means they would lose many of their surface contacts before freezing and disappear into solution after re-thawing. Cryo-con-servation of adhered cells in defined positions requires very precise control of the conditions...

Safety features are essential to a microwave apparatus. An exhaust fan draws the air from the oven to a solvent vapor detector. Should solvent vapors be detected, the magnetron is shut off automatically while the fan keeps running. Each vessel has a rupture membrane that breaks if the pressure in the vessel exceeds the preset limit. In the case of a membrane rupture, solvent vapor escapes into an expansion chamber, which is connected to the vessels through vent tubing. To prevent excessive pressure buildup, some manufacturer use resealable vessels. A spring device allows the vessel to open and close quickly, releasing the excess pressure. 

Some cytotoxicity assays, such as dye incorporation by dead cells or 51Cr or fluorescein release by labeled cells, offer instantaneous results and are named viability tests. These tests are adequate for the identification of dead cells, but can overestimate cell survival over longer periods. Most of them cause membrane rupture and cell death. 

Apoptotic features have been occasionally found in other cardiac disorders in humans [128-131] and experimental models [107, 132-135]. Takemura et al. [135] studied Fas-induced cardiomyocyte apoptosis by electron microscopy, and found extensive condensation of nuclear chromatin and shriveled cytoplasm, fragmented nuclei, and apoptotic bodies. Apoptotic features correlated with positivity for TUNEL and caspase-3. A distinct morphological feature was the abundance of lipid-like structures in the cytoplasm at the early phase and high incidence of plasma membrane rupture at the later phase. Apoptotic bodies were observed to be phagocytosed by neighboring cardiomyocytes. 

A rigid, nonconducting tank with a volume of 4 m3 is divided into two equal parts by a thin membrane. On one side of the membrane the tank contains nitrogen gas at 5 bar and 80°C, and the other side is a perfect vacuum. The membrane ruptures and the gas fills the tank. What is the final temperature of the gas How much work is done Is the process reversible Describe a reversible process by which the gas can be returned to its initial state. How much work is done Assume nitrogen an ideal gas for which CP = (7/2)R and Cv = (5/2)R. 

Comparison of Eq. (3.124) and the above one shows that at a given value of C, xei < r if q > 0, which means that the lifetime of a bilayer membrane is shorter in the presence of external electric field. Increasing V greatly decreases xei and above a critical applied voltage Vt the bitayer membrane ruptures in less than rc seconds. With the above expression of tsi and Eq. (3.129) from the condition Tei(C, Vc) = rc we find that the experimentally accessible dependence of V, on C is of the form... 

The aim of the present work is to take a first stab at representing the specificity of the oxide in the initial stages of PL-oxide surface interactions. The hypothesis is that disruption to cell membrane structure inherited from the early electrostatic adsorption stage affects membrane rupture in the overall cell attachment process. 

Gaskets in both dry gas and liquid chlorine systems are made of rubberized compressed asbestos. For wet chlorine gas, rubber or synthetic elastomers are acceptable. PTFE is resistant to both wet and dry chlorine gas and to liquid chlorine up to 200 °C. Tantalum, Hastelloy C, PTFE, PVDF, Monel, and nickel are recommended for membranes, rupture disks, and bellows. 

Laboratory-made all-Teflon bombs, used for low- or medium-pressure work, are also appropriate for microwave-heated digestion [82], especially when fitted with pressure-relief holes, valves, or membranes (rupture discs). 

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