Fibrous factors determining

Since fibrous monolithic ceramics are intended for use in applications where stresses are primarily generated due to bending, strength and work-of-fracture in flexure are measured to evaluate their basic mechanical properties. In addition, factors determining the manner of crack propagation should be... 

The fact that cartilage, bone and fibrous tissue generating cells are readily inter-changable indicates that the individual progenitor cells share the same genetic information. The question thus comes up what factor or cofactors determine the direction of cellular flow ... 

The CRP levels were determined in these patients. It was higher in patients with plaque rupture (21 patients) compared with those without plaque rupture (24 patients)—3.1 0.5 mg/L versus 1.9 0.4mg/L (P = 0.04). This suggests that an elevated CRP reflects an inflammatory process that can lead to plaque rupture. The CRP seems to have independent predictive capacity for identifying inflammation here. There is also a possibility that CRP may release factors that further weaken the plaque s fibrous cap and allow rupture or erosion (16). 

Give an account of the more important factors that determine whether a protein will be in a fibrous or globular form. 

Recently, part of the mechanism for eye growth in myopia has been determined. Induction of myopia leads to decreased glycosaminoglycan synthesis, increased levels of matrix metalloproteinase-2, and decreased amounts of tissue inhibitor of matrix metalloproteinase-2 in the fibrous sclera of both chicks and tree shrews (65,66), while transforming growth factor (TGF)-p-2 regulates the visual eye growth in the final steps (67). 

It seems evident that (1) if bile acid elimination is inhibited or impaired as a primary phenomenon, e.g., in biliary obstruction and hypercholesterolemia, a decreased catabolism of cholesterol leads to hypercholesterolemia and reduced cholesterol synthesis (2) if bile acid elimination is primarily augmented, e.g., after an external bile fistula, ileal bypass, ileal resection, cholestyramine treatment, or perhaps a diet rich in fibrous material, conversion of cholesterol to bile acids is enhanced, leading almost always, despite stimulated cholesterol synthesis, to a fall in serum cholesterol (3) if endogenous cholesterol production is primarily increased, e.g., by obesity and excess of calories, bile acid synthesis and elimination are augmented, preventing together with increased neutral sterol elimination in some but not all cases the increase of serum cholesterol. This suggests that removal, not production, of cholesterol is the primary factor which determines serum cholesterol level. 

Solvent volatility is also an important factor in determining the properties of fibrous structures produced by electrospinning. In the electrospinning process, solvent evaporation occurs while the jet travels from the tip of the syringe to the collector. If all of the solvent evaporates on the way, fibers can be formed and deposited on the collector. However, if some solvent remains on the pol5mier, instead of dry fibers, wet fibers or thin films can be produced. Solvent volatility might play a role on the formation of pores in the fibers. A decrease in the solvent volatility resulted in a smoother fiber surface. Low-boiling-point solvents are desirable because evaporation of the solvent is enhanced and deposition of the fibers becomes easier. A rapid evaporation rate of the solvent can cause the fibers to form as ribbons with various cross sections. 

The material properties that affect the electrospiiming process and the fibre morphology include the polymer concentration, the solution viscosity, the solution conductivity, the surface tension and other properties concerning the solvent as weU as the polymer itself. Among the material properties, the solution concentration plays a major role in stabilizing the fibrous stmcture because it also affects other solution properties, such as the solution viscosity, the surface tension and the conductivity. The solvent used is another important factor because it mainly determines the surface tension and the evaporation process. The volatility of the solvent affects the fibre surface morphology and the web structure. 

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