Spider web

FIGURE 9.29 Analysis of natural spider silk (spider web). Columns PSS PFG 100 + 1000. Eluent HFIP + 0.1 M KtFat. Temp 2S°C. Detection UV 2S4 nm, Rl. Calibration PSS PMMA ReadyCal kit. 

The feeling of a spider web may be unsettling, but a similar natural material has been used for centuries to make silk fabric that is prized for its smooth texture. Silkworms produce the silk fibers used to make clothing. They feast on mulberry leaves and convert the molecules from these leaves into silk, from which they spin cocoons. 

In a further improvement, the NTD Ge spider-web bolometer developed by the Caltech/JPL group [69], and shown in Fig. 15.10, the absorber is a metallized silicon nitride spider-web structure, and the thermometer is a very small NTD germanium crystal [14], The spacing of the web pattern is much smaller than the wavelength, so it acts... 

Nido-cluster (a nest) a deltahedral structure with one missing vertex. Arachno-cluster (a spider-web) a deltahedral structure with two missing vertices. Hypho-cluster (a net) a deltahedral structure with three missing vertices. 

The II-A isotherms suggest an orientation that aligns the long axis of the polymer rod in the plane of the interface with the EO chains of the hydrophilic dendrons extended into the water layer and the hydrophobic dendrons pointed upward from the surface. The stability of the dendronized polymers likely arises from the balance between the polar and nonpolar regions exposed at the surface of the polymeric cylinder (Bo et al. 1999 Schluter and Rabe 2000). Ariga and colleagues (2004) constmcted a series of spider web dendritic amphiphiles that project hydrophilic Lys-Lys-Glu tripeptides and hydrophobic chains at each generational level (Fig. 11.42). 

This arrangement projects hydrophobic and hydrophilic surfaces above and below the plane of the dendron in a display that mimics the two-dimensional structure of lipid clusters. Accordingly, the amphiphile can efficiently spread out along the surface like a spider web. The II-A isotherms revealed that these molecules form stable monolayers with collapse pressures in the range of 40-60 mN/m. The addition... 

Figure 11.42 (Top) Structures of spider web dendritic amphiphiles. (Bottom) Schematic representation of the molecular orientation at the water-air interface. Reprinted from Ariga et al. (2004). Copyright 2004 American Chemical Society.

In this chapter we consider theories of scattering by particles that are either inhomogeneous, anisotropic, or nonspherical. No attempt will be made to be comprehensive our choice of examples is guided solely by personal taste. First we consider a special example of inhomogeneity, a layered sphere. Then we briefly discuss anisotropic spheres, including an exactly soluble problem. Isotropic optically active particles, ones with mirror asymmetry, are then considered. Cylindrical particles are not uncommon in nature—spider webs, viruses, various fibers—and we therefore devote considerable space to scattering by a right circular cylinder. 

Stowe, M. K. (1986). Prey specialization in the Araneidae. In Spiders Webs, Behavior, and Evolution, ed. W. A. Shear, pp. 101-131. Stanford, CT Stanford University Press. 

What is most remarkable is that cells can produce proteins with strikingly different properties and activities by joining the same 20 amino acids in many different combinations and sequences. From these building blocks different organisms can make such widely diverse products as enzymes, hormones, antibodies, transporters, muscle fibers, the lens protein of the eye, feathers, spider webs, rhinoceros horn, milk proteins, antibiotics, mushroom poisons, and myriad other substances having distinct biological activities (Fig. 3-1). Among these protein products, the enzymes are the most varied and specialized. Virtually all cellular reactions are catalyzed by enzymes. 

Some protein structures limit the kinds of amino acids that can occur in the J3 sheet. When two or more /3 sheets are layered close together within a protein, the R groups of the amino acid residues on the touching surfaces must be relatively small. J3-Keratins such as silk fibroin and the fibroin of spider webs have a very high content of Gly and Ala residues, the two amino acids with the smallest R groups. Indeed, in silk fibroin Gly and Ala alternate over large parts of the sequence. 

FIGURE 4-14 Structure of silk. The fibers used to make silk cloth or a spider web are made up of the protein fibroin, (a) Fibroin consists of layers of antiparallel /3 sheets rich in Ala (purple) and Gly (yellow) residues. The small side chains interdigitate and allow close packing... 

Only a few samples were taken from the alleged homicidal gas chambers. Care was taken to ensure that samples were only taken from material not exposed to weathering. Only a few places in morgue 1 (the alleged gas chamber ) in crematorium II at Birkenau, where a pillar supports the roof even today and has therefore visibly protected both the underside of the roof and parts of the wall from all influence of weathering, exemplified by the deposition of spider webs many years old and the absence of any trace of lime precipitation on the concrete or mortar, which would be caused by rain water. 

There are seven compounds with OAV > 1 in the Madeira wines analyzed. These compounds are displayed in a spider-web (Fig. 7.5). 

FIGURE 7.5 Spider-web for the odorants with OAV 1 for the four young Madeira wines studied (adapted from Camara, 2004). 

FIGURE 8.5 Spider web diagram of sensory qualities of wild apricot vermouth of different sugar levels (source Abrol, 2009). 

Pull out the DNA. It will look like mucus or egg white. As it dries, it will look like a spider web. The fibers are millions of DNA strands. 

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