Sampling interior/exterior

CT offers the opportunity to examine slices through the sample non-destructively and is therefor the only method for measuring exterior and also interior part coordinates without mechanical cutting of the object. 

Essentially the same amino acids, and nearly equal quantities of D and L enantiomers, were detected in the Murray meteorite, another type II carbonaceous chondrite [6]. Recent expeditions to Antarctica have returned with a large number of meteorites, many of which are carbonaceous chondrites. These may have been protected from terrestrial contamination by the pristine Antarctic ice. Careful analysis of two of these, the Yamato (74662) and the Allan Hills (77306), both type II carbonaceous chondrites, by ion exchange chromatography, gas chromatography, and GC/MS, have detected a wide variety of both protein and non-protein amino acids in approximately equal D and L abundances [9,10]. Fifteen amino acids were detected in the Yamato meteorite and twenty in the Allan Hills, the most abundant being glycine and alanine. The amino acid content of the Yamato meteorite is comparable with that of the Murchison and Murray, but the Allan Hills contains 1/5 to 1/10 that quantity. Unlike earlier meteorites from other locations, the quantities of amino acids in the exterior and interior portions of the Yamato and Allan Hills meteorites are almost identical [9,10]. Thus, these samples may have been preserved without contamination since their fall in the blue ice of Antarctica, which js 250,000 years old in the region of collection. 

If there are different colored residues on different areas of the shard, e.g., the interior compared to the exterior, sample and label separately. 

A porous particle contains many interior voids known as open or closed pores. A pore is characterized as open when it is connected to the exterior surface of the particle, whereas a pore is closed (or blind) when it is inaccessible from the surface. So, a fluid flowing around a particle can see an open pore, but not a closed one. There are several densities used in the literature and therefore one has to know which density is being referred to (Table 3.15). True density may be defined as the mass of a powder or particle divided by its volume excluding all pores and voids. True density is also referred to as absolute density or crystalline density in the case of pure compounds. However, this density is very difficult to be determined and can be calculated only through X-ray or neutron diffraction analysis of single-crystal samples. Particle density is defined as the mass of a particle divided by its hydrodynamic volume. The hydrodynamic volume includes the volume of all the open and closed pores. Practically, the hydrodynamic volume is identified with the volume included by the outer surface of the particle. The particle density is also called apparent or envelope density. The term skeletal density is also used. The skeletal density of a porous particle is higher than the particle one, since it is the mass of the particle divided by the volume of solid material making up the particle. In this volume, the closed pores volume is included. The interrelationship between these two types of density is as follows (ASTM, 1994 BSI, 1991) ... 

Field Sampling. An opportunity arose where actual field samples could be analyzed by both the infrared and gas chromatographic methods. At Robins AFB, Georgia, workers were inspecting and repairing the interior and exterior of C-141 aircraft fuel tanks. They were exposed only to JP-4 fuel fumes. Duplicate charcoal tubes or vapor monitors were attached to each worker, one on each lapel. Samples were drawn through the charcoal tubes at 0.20 to 0.26 1pm by portable pumps attached to the worker s belt. Because of slight variations, the total volumes collected for the duplicates were close, but not exactly the same in all cases. Samples were then labeled and shipped to our Laboratory for analysis by both methods. 

Fig. 69 Picture of a room located in the northwest of the disinfestation wing of building 5a (see Figure 18). The exterior walls are located in the background and to the right, showing intensive blue discolorations caused by iron Blue. Taking locations of samples 9 and 11 are visible. On the left in the picture is the interior wall, erected during the conversion to a hot air disinfestation chamber. Sample 10, with a slightly positive cyanide content, was taken from this wall.

Self-shadowing and resonance capture effects. The use of small samples and standards so that the neutron flux is not appreciably attenuated between the exterior and interior of the irradiation unit is to be desired. When large samples are used or appreciable high cross section material is present in the matrix, it is important that the standard be prepared with a matrix physically and chemically similar to that of the sample. 

The performance of protein or antibody microarrays is dependent on various factors. One of these is the use of an appropriate microarray surface for the immobilization of the protein or antibody samples. Most conventional microarray surfaces have been adapted from DNA chip technology. DNA can easily be immobilized by electrostatic interactions of the phosphate backbone onto a positively charged surface. In contrast to DNA, as already mentioned, proteins are chemically and structurally much more complex and show variable charges, which may influence the efficiency of protein attachment. Additionally, proteins lose their structure and biochemical activity easily. For example, globular proteins consist of a hydrophilic exterior and a hydrophobic interior. When immobilized on a hydrophobic surface, the inside of the protein turns out, which may destabilize the structure and, simultaneously, the activity of the protein. These considerations demonstrate the complex requirements for protein immobilization. 

The basic idea of the dynamic pressurization (DP) experiment is similar to the dynamic gas expansion (DGE) method. Both use a sudden pressure change around a gel specimen to initiate gas flow into or out of the sample, thus avoiding the delicate leakage problems typically encountered in static gas flow setups. While DGE monitors the gas pressure outside the gel as a function of time and deduces the permeability from its equilibration behavior (in principle a dynamic pycnometry experiment). DP utilizes the dynamics of the elastic deformation of the gel to deduce both elastic modulus and permeability. The deformation, or strain, is a consequence of the pressure difference between the interior and the exterior of the specimen. For example, after a sudden increase in pressure, the gas in the gel pores is initially only slightly compressed along with the elastic compression of the gel. After a characteristic time, the pressure equilibrates and the gel ideally springs back to its original dimensions. 

Sample C.L. fi-Atnylolysis limit, % Exterior chain length Interior chain length References... 

Apart from differences in molecular weight, 14 of the 16 samples show little variation in branching characteristics the constituent chains contain 10 -14 D-glucose residues per end-group, and 41-51 % of these are removed, as maltose, by /3-amylase. The average interior and exterior chain-lengths are, therefore, approximately 3 and 8 n-glucose residues, respectively. 

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