From Liquid Media

Using a transfer loop, place one or two loops of the hquid containing the microorganism on the microscope slide. 

Allow the smear to dry at room temperature. Avoid the temptation to accelerate the drying process by exposing the preparation direcdy to heat from the flame. 

Once the smear is dry, heat fix the microorganisms to the slide hy attaching a clothespin to a short side of the slide and passing the slide through an open flame. 

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Difficulty arises when one is attempt to produce clusters composed of molecules vulnerable to heat. Biological molecules such as proteins and DNA molecules are in this category. The laser ablation is unlikely to prepare clusters of such biological molecules, because a considerable extent of fragmentation is inevitable concurrently with the laser ablation. In order to overcome this difficulty, several techniques have been developed to isolate biological molecules and those with solvent molecules (water etc.) from liquid media the biological molecules are known to have their bioactive... 

We have reviewed several methodologies of isolation and detection of molecules and clusters from liquid media into the gas phase, with a detailed description on the method based on the liquid beam technique. The methodologies of the isolation and the detection are particularly powerful and versatile for the studies of isolated biological molecules, which provide useful information on the understanding of the functions of the biological... 

Changing the reaction medium. If water is replaced by an organic solvent in syntheses, contamination of wastewater can often be drastically reduced. However, environmentally friendly solvent handling involves not only recovery of the solvent from liquid media but also prevention of losses to the atmosphere during storage, transport, production, and subsequent processing. This can be achieved, for example, by adsorptive recovery of solvents from the gas stream. 

Solid-phase extraction (SPE) SPE is used for isolation of the target compounds from liquid media by means of adsorption on a granular solid bed... 

Solid-phase microextraction (SPME) SPME consists in the adsorption of the target compounds on a thin polymeric film deposed on the surface of a capillary fiber. The mass transfer can be achieved from liquid media in direct contact with the extracting coated fiber as well as from gaseous environments. Volatile or semivolatile herbicides existing in solid samples can be easily transferred in the gas phase on heating in closed vials, followed by trapping of the resulting vapors in the coated fiber (procedure is known as Headspace HD/SPME). 

The removal of ochratoxin A and patulin from solution by 30 different LAB was studied by Fuchs et al. (2008). Results showed thatL. acidophilus was able to remove at least 95% of ochratoxin A from liquid medium, while Bifidobacterium animalis was able to bind and remove 80% of patulin in solution. Hatab, Yue, and Mohamad (2012) also studied the ability of LAB strains to remove patuhn from liquid medium, in this case apple juice. All 10 strains used in the experiments were able to remove the toxin, at significantly different amounts, with best binding ability shown by L rhamnosus 6224 (80.4%) and Enterococcus faecium 21605 (64.5%). According to the authors, the optimal mycotoxin removal was achieved at 30 °C, the binding was toxin concentration dependent (the amount of toxin removal increased with decreasing toxin levels) and the adsorption of patulin by LAB had no negative impact on the quality of the apple juice, based on various quahty parameters (Hatab et al., 2012). 

Lactobacillus and Propionibacterium strains were evaluated by El-Nezami et al. (2002) regarding their ability to remove seven Fusarium toxins (trichothecenes) from solution. Results showed that L. rhamnosus GG and Propionibacterium freudenrei-chii spp. shermanii JS were able to bind 18-93% of the deoxynivalenol, diacetoxy-scirpenol, and fusarenon in solution, while L. rhamnosus LC-705 removed 10-64% of deoxynivalenol and diacetoxyscirpenol from liquid medium. When comparing the ability of lactic and propionic bacteria to remove toxin from solution, Niderkom, Boudra, and Morgavi (2006) found that deoxynivalenol and fumonisin removal was strain specific, and that in general propionic acid bacteria was less efficient than lactic acid bacteria. The best results were achieved with L. rhamnosus for ranoval of deoxynivalenol (55%), Leuconostoc mesenteroides for fumonisin Bi (about 82%), and L. lactis for fumonisin B2 (100%) (Niderkom et al., 2006). 

Liquid diops, suspended in a continuous liquid medium, separate according to the same laws as solid paiticles. Aftei reaching a boundary, these drops coalesce to form a second continuous phase separated from the medium by an interface that may be well- or ill-defined. The discharge of these separated layers is controlled by the presence of dams in the flow paths of the phases. The relative radii of these dams can be shown by simple hydrostatic considerations to determine the radius of the interface between the two separated layers. The radius is defined by... 

Filtration is the separation of a fluid-solids mixture involving passage of most of the fluidthrough a porous barrier which retains most of the solid particulates contained in the mixture. This subsec tion deals only with the filtration of solids from liquids gas filtration is treated in Sec. 17. Filtration is the term for the unit operation. A filter is a piece of unit-operations equipment by which filtration is performed. The filter medium or septum is the barrier that lets the liquid pass while retaining most of the solids it may be a screen, cloth, paper, or bed of solids. The hquid that passes through the filter medium is called the filtrate. 

In the filtration of small amounts of fine particles from liquid by means of bulky filter media (such as absorbent cotton or felt) it has been found that the preceding equations based upon the resistance of a cake of solids do not hold, since no cake is formed. For these cases, in which filtration takes place on the surface or within the interstices of a medium, analogous equations have been developed [Hermans and Bredee, J. Soc. Chem. Ind., 55T, 1 (1936)]. These are usefully summarized, for both constant-pressure and constant-rate conditions, by Grace [Am. In.st. Chem. Eng. J., 2, 323 (1956)]. These equations often apply to the clarification of such materials as sugar solutions, viscose and other spinning solutions, and film-casting dopes. 

In a filtering centrifuge, separating sohds from liquid does not require a density difference between the two phases. Should a density difference exist between the two phases, sedimentation is usually at a much more rapid rate compared to filtration. In both cases, the solid and liquid phases move toward the bowl under centrifugal force. The sohds are retained by the filter medium, while the liqmd flows through the cake solids and the filter. This is illustrated in Fig. 18-138/ . 

Several manual and continuous analytical techniques are used to measure SO2 in the atmosphere. The manual techniques involve two-stage sample collection and measurement. Samples are collected by bubbling a known volume of gas through a liquid collection medium. Collection efficiency is dependent on the gas-liquid contact time, bubble size, SO2 concentration, and SO2 solubility in the collection medium. The liquid medium contains chemicals which stabilize SO2 in solution by either complexation or oxidation to a more stable form. Field samples must be handled carefully to prevent losses from exposure to high temperatures. Samples are analyzed at a central laboratory by an appropriate method. 

The theory of filtration of aerosols from a gas stream is much more involved than the sieving action which removes particles in a liquid medium. Figure 29-1 shows three of the mechanisms of aerosol removal by a filter. In practice, the particles and filter elements are seldom spheres or cylinders. 

The hydrostatic pressure varies from a maximum at the point where suspension enters the cake, to zero where liquid is expelled from the medium consequently, at any point in the cake the two are complementary. That is, the sum of the hydrostatic and compression pressures on the solids always equals the total hydrostatic pressure at the face of the cake. Thus, the compression pressure acting on the solids varies from zero at the face of the cake to a maximum at the filter medium. 

A heat exchanger is a device that transfers heat from one medium to another the medium may be a solid, liquid, or gas. Some of the most complex engineering design problems relate to heat exchangers. 

In suspension polymerization, the monomer gets dispersed in a liquid, such as water. Mechanical agitation keeps the monomer dispersed. Initiators should be soluble in the monomer. Stabilizers, such as talc or polyvinyl alcohol, prevent polymer chains from adhering to each other and keep the monomer dispersed in the liquid medium. The final polymer appears in a granular form. 

Penicillins, like most antibiotics, are secondary products whose synthesis is not directly linked to growth. The enzymes that produce secondary products are normally repressed or inhibited under conditions which favour rapid growth. In the early work on penicillin, Penicillium rwtatum was grown as a floating mycelium on about 2 cm depth of liquid medium. The mycelium absorbed nutrients from the medium and penicillin was excreted into the medium. The mycelium and spent medium are readily separated. 

Chemically active plastics such as the polyelectrolytes have been used to make artificial muscle materials. This is an unusual type of mechanical power device that creates motion by the lengthening and shortening of fibers made from a chemically active plastic by changing the composition of the surrounding liquid medium, either directly or by the use of electrolytic chemical action. Obviously this form of mechanical power generation is no competitor to thermal energy sources, but it is potentially valuable in detector equipment that would be sensitive to the changing... 

The gas-phase photolysis of 2-furaldehyde in the it -n and ir <-it transitions76 proceeds with fragmentation to CO, furan and C3-hydrocarbons, but a certain amount of resinification is also noted (about 5% quantum yield with excitation of the it - n transition). The latter observation prompted a study of the vacuum liquid-phase photolysis by sunlight or by light from a medium-pressure mercury arc at room temperature24 7S. The resin obtained was submitted to fractionation and structural analysis. On the basis of the results obtained and other mechanistic evidence, the following sequence of events was postulated for the photopolymerization ... 

There is also some evidence that the ionic liquid medium affects polymer structure. Biedron and Kubisa150 reported that the tacticity of PMA prepared in the chiral ionic liquid 19 is different from that prepared in conventional solvent. It is also reported that reactivity ratios for MMA-S copolymcrization in the ionic liquid IS161 differ from those observed for bulk copolymerization. 

Bubble-column slurry operations are usually characterized by zero net liquid flow, and the particles are held suspended by momentum transferred from the gas phase to the solid phase via the liquid medium. The relationships between solids holdup and gas flow rate is of importance for design of bubble-column slurries, and some studies of this aspect will be reviewed prior to the discussion of transport phenomena. 

For NRt < 1, the problem of bubble motion is closely related to that of the motion of a liquid drop in a liquid medium, and can consequently be derived from the Rybczynski-Hadamard formula (H2, R13) ... 

The isolates were cultured in 100 ml Erlenmeyer flasks containing 20 ml liquid medium (12) with different carbon sources. The cultures were inoculated with mycelial disks cut from the margins of 7 day-old-colonies and incubated at 25 ( under static conditions. 

They showed further that the limiting slope (RTA2) of the plot of the osmotic pressure-concentration ratio tz/c against the polymer concentration in a binary solvent mixture should be proportional to the value of the quantity on the left side of Eq. (17),f with V2 representing the volume fraction of solvent in the nonsolvent-solvent mixture which is in osmotic equilibrium with the solution. The composition of the liquid medium outside the polymer molecules in a dilute solution must likewise be given by V2. The composition of the solvent mixture within the domains of the polymer molecules may differ slightly from that outside owing to selective absorption of solvent in preference to the nonsolvent. This internal composition is not directly of concern here. If the solution is made sufficiently dilute, the external nonsolvent-solvent composition v2 = l—Vi) will be practically equal to the over-all solvent composition for the solution as a whole. Hence... 

The naming of the micro channel device stems from the prevailing flow pattern related to the guidance bubbles through a continuous liquid medium [3,9,... 

PGSE-NMR provides direct information on the translational mobility of a liquid medium capable of swelling a given CFP. The self-diffusion coefficient of the swelling agent is found to be related to the nanoporosity of the matrix as determined from ISEC and to the rotational correlation time of a suitable paramagnetic probe (ESR) [22]. 

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