Tubular growth

The first study using a wet cell, made at high w/c ratios, showed tubular growths radiating from the cement grains, which were considered to have formed by a silicate garden mechanism (D14). Later work showed that they were rich in calcium, aluminium and sulphur, and that they did not form if CjS was substituted for cement (BlOl). They have not been observed in the more recent studies made at normal w/c ratios, and do not appear to be a significant feature of normal cement hydration. 

FIGURE 18.49 Mesothelioma. (A) A tubular growth pattern and the cuboidal appearance of the tumor cells usually differentiate mesothelioma from serous carcinoma, but in some cases the histologic patterns overlap. (B) Mesothelioma shows strong cytoplasmic and nuclear staining for calretinin, as shown here. 

Thouvenel-Romans, S., Pagano, ).)., and Steinbock, O. (2005) Bubble guidance of tubular growth in reaction-precipitation systems. Phys. Chem. Chem. Phys., 7, 2610-2615. 

The above situation should be clearly distinguished from the case of rods when p = 1 and the mean aggregation number can be shown [26], at variance with the case of disks and spheres, to be concentration-dependent producing broad size distributions (as observed in the case of actin. Fig. 27). In fact, as recognized early by Oosawa and Asakura [2], helical or tubular growth has features intermediate between the continuous growth described by MSOA and a true phase transition. 

As it was established by Geus et a/.[18, 19] the decrease of the rate of carbon deposition is a positive factor for the growth of fibres on metal catalysts. Si02 is an inhibitor of carbon condensation as was shown in Ref [20]. This support also provides possibilities for the stabilization of metal dispersion. Co and Fe, i.e. the metals that give the best results for the tubular condensation of carbon on graphite support, were introduced on the surface of siUca gel... 

In a common method for the production of tubular carbon fibers, the growth is initiated by submicrometer size catalytic metal particles[19]. Tube growth out of a graphite rod during arc-discharge might also be related to nanoparticle-like seeds present... 

Biological indicators (Bis) for use in thermal, chemical or radiation sterilization processes consist of standardized bacterial spore preparations which are usually in the form either of suspensions in water or culture medium or of spores dried on paper, aluminium or plastic carriers. As with chentical indicators, they are usually placed in dummy packs located at strategic sites in the sterilizer. Alternatively, for gaseous sterihzation these may also be placed within a tubular hehx (Line-Pickerill) device. After the sterilization process, the aqueous suspensions or spores on carriers are aseptically transferred to an appropriate nutrient medium which is then incubated and periodically examined for signs of growth. Spores of Bacillus stearothermophilus in sealed ampoules of cultrrre medium are used for steam sterilization morritoring, and these may be incubated directly at 55°C this eliminates the need for an aseptic transfer. 

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