Glass chambers

Fig. 7. A bead filter, one of many types of biological filters, shown in association with a laboratory-scale recirculating water system. Small plastic beads inside the fiber glass chamber provide surface area for colonisation by bacteria that convert ammonia to nitrate.

For four years, Muller synthesized his own compounds and almost single-handedly screened them for their effect on houseflies. They were known to be transmitters of intestinal diseases like dysentery, and it was speculated at the time that they might spread polio. Muller built a cubic-meter glass chamber for insects and sprayed compound after compound at them. As soon as one compound seemed promising, he searched more carefully among its close relatives, using the natural insecticides, rotenone and pyrethrum, as controls. 

In a 90-d study with a 4-wk interim sacrifice, groups of 15 male and 15 female Fischer 344 rats were exposed at 0, 2,000, 8,000, or 20,000 ppm for 6 h/d, 5 d/wk in a 4 m3 stainless steel and glass chamber (Brock et al. 1995). Chamber concentrations were measured by infrared spectrometry. The animals were examined daily, and body weights and food consumption were measured weekly. Prior to sacrifice, blood and urine samples were collected. At the end of 4 wk, five rats per gender per group were sacrificed, and organs... 

We have developed and tested a metabolism system and regimen which allows collection of data comparable to those from terrestrial animals. The key to our experiments is a metabolism chamber, described previously Cl3, 14) CFig. 1), which can be operated in either the static or flow-through mode. Briefly, individuals or groups of animals are held at constant temperature in the jacketed glass chamber (A), on a stainless steel screen (B), while pure water or test solution is passed over them (or held under static conditions). Solid wastes are separated in a jacketed container (C) held near 0°C to minimize microbial action, and the effluent containing dissolved metabolites is passed onto a column of nonionic macroreticular adsoprtion resin where organic solutes are adsorbed from solution (D). 

By 1963, we had done considerable testing of LSD by the oral route, but we knew the military was more interested in the effectiveness of the respiratory route. Our first study of aerosolized LSD made use of an ancient Devilbiss nebulizer, a glass device relied on for decades by asthma sufferers. We partially filled its glass chamber with a very dilute solution of LSD in distilled water. 

Glass reactors Many studies have been carried out in borosilicate glass reactors similar to those used in typical laboratory studies of gas-phase reactions. These are usually relatively small, a few liters up to approximately 100 L (0.1 m3). However, Doussin et al. (1997) have developed a borosilicate glass chamber with a volume of 977 L by using four cylinders held together by flanges. 

Volatile pheromones from spiders are more difficult to analyze because the site of the pheromone-producing organs is not known. Good results have been obtained by collection of volatiles released into the airspace around a spider. For example, single individuals of A. aperta confined in 50 ml glass chambers emitted enough material for analysis (Papke et al, 2001). Probable pheromone components were deduced by comparison of samples collected from individuals that had been shown to be attractive or unattractive to males. Abdominal wipes afforded similar quantities of... 

Figure 5.2 Different types of devices for emission testing A Field and Laboratory Emission Cell (FLEC) B WKI 1 m3 glass chamber with Fast Mobility Particle Sizer (FMPS) C 1 m3 stainless steel chamber D Microchamber E WKI 48m3 stainless steel chamber.

Figure 5.4 Decay curves of 1 -bromo-3-chloro-benzene in the 1 m3 glass chamber ( ) with sink (gypsum board) ( ) without sink ( ) theoretical decay (Uhde and Salthammer,...

Personal computers (PCs) are important sources of VOCs in office and homes (Bako-Biro et al., 2004).Thus, the TVOCs emission rate per PC observed in a glass chamber study was as high as 486.6 pg/h while individual emission rates for toluene and phenol were 47 and 63 pg/h respectively. Other prominent chemicals emitted by PCs include, 2-ethylhexanol, formaldehyde and styrene (Bako-Biro et al., 2004). (See Chapter 17 for a more detailed discussion of VOCs in electronic devices.)... 

A small magnetic stirring bar (2 mm dia. x 7 mm) was used to enhance mixing in a PDMS-glass chamber (50 iL). This led to a three- to four fold increase in the DNA hybridization efficiency [490],... 

There are two popular LC techniques in which the stationary bed is supported on a planar surface rather than in a column paper chromatography (PC) and thin-layer chromatography (TLC). PC preceded TLC by some 10 to 15 years, and a large number of excellent separations were devised for it. But beginning about 1956, it was found that TLC could also be used for most of these separations and that it was faster, more reproducible, more versatile, and more convenient. As a result, most laboratories have abandoned the use of PC with its large cumbersome glass chambers. Those who have not, continue to use PC because they feel that the original PC methods are superior or because of the lower cost of PC. 

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