White normal appearing

When initiator is first added the reaction medium remains clear while particles 10 to 20 nm in diameter are formed. As the reaction proceeds the particle size increases, giving the reaction medium a white milky appearance. When a thermal initiator, such as AIBN or benzoyl peroxide, is used the reaction is autocatalytic. This contrasts sharply with normal homogeneous polymerizations in which the rate of polymerization decreases monotonicaHy with time. Studies show that three propagation reactions occur simultaneously to account for the anomalous auto acceleration (17). These are chain growth in the continuous monomer phase chain growth of radicals that have precipitated from solution onto the particle surface and chain growth of radicals within the polymer particles (13,18). 

Unsaturated polyesters that are terminated by carboxylic acid groups at both ends of the chain after neutralization are efficient emulsifiers for lipophilic monomers [110] and thus act as self-emulsifying crosslinking agents in the ECP of these systems. Normal emulsions of EUP and comonomers have a white, milky appearance. With an appropriate structure and molar mass of the EUP and within a certain range of EUP/comonomer ratios, however, microemulsions are... 

O Sullivan M, Summers PE, Jones DK, Jarosz JM, Williams SC, Markus HS (2001) Normal-appearing white matter in ischemic leukoaraiosis a diffusion tensor MRI study. Neurology 57 2307-2310... 

In conclusion, the deformation behavior of poly(hexamethylene sebacate), HMS, can be altered from ductile to brittle by variation of crystallization conditions without significant variation of percent crystallinity. Banded and nonbanded spherulitic morphology samples crystallized at 52°C and 60°C fail at a strain of 0.01 in./in. whereas ice-water-quenched HMS does not fail at a strain of 1.40 in./in. The change in deformation behavior is attributed primarily to an increased population of tie molecules and/or tie fibrils with decreasing crystallization temperature which is related to variation of lamellar and spherulitic dimensions. This ductile-brittle transformation is not caused by volume or enthalpy relaxation as reported for glassy amorphous polymers. Nor is a series of molecular weights, temperatures, strain rates, etc. required to observe this transition. Also, the quenched HMS is transformed from the normal creamy white opaque appearance of HMS to a translucent appearance after deformation. 

Recent evidence obtained via magnetic resonance imaging and spectroscopy techniques supports the view that the normal-appearing white matter (NAWM) in the MS brain is altered. Several biochemical changes in NAWM have been determined. These include the cationicity of myelin basic protein (MBP) as a... 

Lindberg RL, DeGroot CJ, Certa U, Raviol T, Hoffmann F, Kappos L, Leppert D (2004) Multiple sclerosis as a generalized CNS disease—comparadvemicroarTay analysis of normal appearing white matter and lesions in secondary progressive multiple sclerosis. J Neuroimmunol 152 154—167. 

Axonal injury may occur not only in the late phases of MS but also after early episodes of inflammatory demyelination (Lucchinetti et al., 1999 Trapp et al., 1998 Bitsch et al., 2000 De Stefano et al., 2001). Gray matter lesions and axonal injury in normal appearing white matter are reported in MS implying that axonal injury could trigger demyehnation (Tsunoda and Fujinami, 2002). The pathogenesis of this early axonal injury is still unclear. 

FIGURE 4.3 Blood-brain barrier disruption as revealed by computerized tomography A. Normal CT scan, before and after injection of the enhancement material, Omnipaque . Note the enhancement (hyperdense white) in brain arteries and vein sinuses (wide arrows) without penetration into the brain parenchyma. B. A case of multiple brain metastases in a 41-year-old female with a history of breast cancer. Following injection of Omnipaque , several round white regions appear, reflecting focal BBB disruption in the regions harboring tumors (thin arrows). 

Electron microscopy of a lung biopsy of a 49-years old white man who had spent 12 years in the manufacturing area revealed markedly altered alveolar lining cells and basement membranes (Coates and Watson 1971). Normal appearing type I pneu-mocytes were absent. 

Sulfur trioxide is a clear, oily, colorless liquid. As shipped, it may contain a haze and be off-white to light brown in appearance. Oleum is normally turbid and off-white in appearance. Their main uses are in the production of plastics, detergents, and dyestuffs (Kirk-Othmer, 1983 Duecker and West, 1971). 

Blooming An area of the target that is unstable due to insufficient beam current The area normally appears as a white puddle without definition. Insufficient beam current maybe the result of a low beam control setting. 

On cross sectioning the brain, cystic areas like those observed in TSD are rarely seen. The white matter appears firmer than normal, the grey matter is softer (Klinken-Rasmussen and Dyggve 1965), and the cerebellum is quite hard. 

Fig. 8.13a,b. Median nerve and brachial artery. Longitudinal gray-scale (a) and color Doppler (b) 12-5 MHz US images over the antecubital fossa demonstrate the normal appearance of the median nerve (white arrows in a) and the brachial artery (open arrows in b). Both lie superficial to the brachialis muscle (hr). Note the humeral capitellum (HC) and the radial head (RH). The inserts at the upper left side of the figures indicate probe positioning... 

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