Created Artifacts

The images shown in this chapter are created using RasMol 2.6, Molecular Graphics Visualisation Tool by Roger Sayle, BioMolecular Structures Group, Glaxo Research Development, Greenford, Middlesex, UK. RasMol can be obtained at http //www.umass.edu/ microbio/rasmol/. The coordinates were obtained from the Protein Data Bank at Brookhaven National Laboratory 

Appleby and R. J. Olds The inherited basis of venous thrombosis. Pathology 29, 341 (1997). 

Banner The factor Vlla/tissue factor complex. Thrombosis and Haemostasis 78, 512(1997). 

Bauer New markers for in vivo coagulation. Current Opinions in Hematology 1, 341 (1994). 

Bode and M. T. Stubbs Spatial structure of thrombin as a guide to its multiple sites of interaction. Seminars in Thrombosis and Hemostasis 19, 321 (1993). 

---

It is important to stress that ATR absorbance is strongly affected by the sample/crystal contact. Quantitative results are thus difficult to obtain even if the contact is maintained during the sample rotation that is required to record all four polarized spectra. A reference band that does not show significant dichroism is thus most often used to normalize the polarized absorbances in order to obtain quantitative data. For instance, the 1,410 cm-1 band of PET has often been chosen for that purpose, not only for ATR studies but also for specular reflectance (see below) and even transmission studies when the sample thickness is not uniform. It was shown that an appropriate normalization is possible even if no such reference band is available, by using a combination of two bands with orthogonal dichroism [34]. When performing ATR experiments, one should also make certain that the applied pressure does not create artifacts by affecting the structure of the sample. 

Development tools Evaluate, purchase, install, use to create artifacts... 

Avoid unrealistically high test concentrations that may create artifacts such as accumulation of undissolved particulates on fish gills... 

Many pulse sequence suppression schemes exist and these can be loosely classified into three broad classes (i) saturation based, (ii) magnetization destruction based, and (iii) methods avoiding solvent saturation. An ideal method would suppress the solvent only with no other effect on the spectrum. In reality this is never the case. For example, some suppression sequences which involve frequency-selective excitation result in frequency-dependent artifacts such as phase shifts and amplitude responses. Sometimes the applicability of a suppression method depends on the sample. For example, in addition to creating artifacts, caution must be taken when using suppression methods that involve saturation since cross-relaxation can result in significant signal loss, especially with large molecules. 

Veblen et al. (1990), Dong and Peacor (1996), and Peacor (1998) questioned the validity of the fundamental particles theory of Nadeau, on the basis of TEM data obtained from quasi-undisturbed whole-rock samples prepared by ion-milling. Their data proved coherency across smectite and illite interlayers and showed also incoherency within larger illitic stacks. As to their interpretation, sample preparation methods conventionally used to XRD and Pt-shadowing TEM techniques may create artifacts (i.e., fundamental particles as coherent crystallites). The relation of these fundamental particles to the crystallites (coherent domains) in the undisturbed rock matrix can and should be questioned and may at least be indirect. 

Sediment traps are intended to measure downward flux, but technical diflBculties may affect interpretation of the results. Loss of trapped material during recovery is still a problem (53,55), and replication is not always good (55) because the traps affect the flow of water around them (cf. Ref. 66). Also, trapping of what is really resuspended benthic material may create artifacts (for example, 67), even a few hundred meters off the bottom of the deep sea (55). 

The idea of emergent synthesis is fundamental and thereby relates all acts of creating artifacts, so that it can be theoretical basis for various production... 

Deployment level consists of the deployment of the created artifacts to construct the production system. 

Matrix The volatiles are frequently intracellular and must be liberated by disruption. The sample frequently contains nonvolatile components such as Upids, proteins, or carbohydrates, which complicates the isolation process. These components may create problems of foaming and emulsification during isolation procedures and will create artifacts if injected into a hot gas chromatography injector port. 

Blind deconvolntion can be subject to bootstrap errors, i.e., if you start with a bad first image (low signal to noise) or iterate too long, yon may create artifacts. 

---