Scented fiber

Abandoning the hunt for linear, fiber-forming molecules, he turned to polymer ring compounds. Before Carothers, cyclic compounds were so difficult to make that no one studied them, but his group had tasted scientific blood and was happily publishing papers. When they discovered a series of ring compounds that produce synthetic scents, Du Pont sold the compounds to the perfume industry. The cyclic compounds were the last of Carothers fundamental scientific studies. After completing them, he drifted for a while, unclear as to what direction his research should take. 

Recently, Rosell and Sundsdal [78] tentatively identified 21 of the 43 constituents present in 96 scent marks deposited directly on snow or ice mounds by the Eurasian beaver, C. fiber. In this study, a higher final oven temperature was employed and several steroids were eluted from the capillary column. Because the main focus of this study was to determine whether the beaver uses castoreum and/or anal gland secretion for scent marking and not the full chem-... 

Unlike most terrestrial mammals, beavers maintain territories along a line following watercourses. Both species, the Eurasian beaver, C. fiber, and the North American beaver, C. canadensis, dredge up mud from the bottom of their home pond, carry it on land, deposit it, and apply a scent mark on top of this mud... 

Rosell, F., Bergan, F., and Parker, H. (1998). Scent marking in the Eurasian beaver [Castor fiber) as a means of territory defense. Journal of Chemical Ecology 24, 207-219. 

Resell F, Nolet BA (1997) Factors affecting scent-marking behavior in Eurasian beaver (Castor fiber). J Chem Ecol 23 673-689... 

Furyl)-8-methyloctahydroindolizine (12) has been isolated from the scent-gland of the Canadian beaver Castor fiber L.), together with (-)-castoramine and a series of related quinolizidines and other alkaloids. The alkaloid (12) is only a minor... 

The previous review on Nuphar (water-lily) alkaloids in this treatise appeared in Volume 35, and covered the period 1974-1987 (7). It overlapped in part with the treatment of simple bicyclic Nuphar metabolites in Volume 28 (7). Nuphar alkaloids include sesquiterpenoid monomeric (C15) piperidine and quinolizidine alkaloids as well as more complex dimeric (C30) sulfur-containing metabolites. Related metabolites isolated from the scent glands of the Canadian beaver, Castor fiber, also include a unique indolizidine alkaloid 944 606). Only the indolizidine and simple quinolizidine alkaloids are relevant to the present review. Compounds mentioned in the ensuing discussion are illustrated in Fig. 18. 

Combining the above described microfluidic differential resistive pulse sensor method with a miniature laser-fiber optic fluorescent detector, the simultaneous detection of fluorescent and non-fluorescent particles has been demonstrated [19], This method is simple, inexpensive, and easy to operate, and can achieve highly sensitive and accurate detection without relying on any conventional bulky instmments. Excellent agreement was achieved by comparing the results obtained by this chip system with the results from a commercial flow cytometer for a variety of samples of mixed fluorescent and non-fluore scent particles. 

To be smelled, a substance must be volatile and it must be at least slightly soluble in water. Odorous molecules bind to specialized proteins, known as receptors, located on hairlike cilia at the rear of the nose. The binding of odors to these receptors triggers an electrical signal that travels along nerve fibers from the olfactory bulb to the brain, where the scent is identified. 

Another major source of contamination in an analysis can be the analyst. It depends on what kind of analytes are being measured, but when trace or ultratrace levels of elements or molecules are being determined, the analyst can be a part of the analytical problem. Many personal care items, such as hand creams, shampoos, powders, and cosmetics, contain significant amounts of chemicals that may be analytes. The problem can be severe for volatile organic compounds in aftershave, perfume, and many other scented products and for sihcone polymers, used in many health and beauty products. Powdered gloves may contain a variety of trace elements and should not be used by analysts performing trace element determinations. Hair, skin, and clothing can shed cells or fibers that can contaminate a sample. 

Rosell, F. 2002, The function of scent marking in beaver (Castor fiber) territorial defence, PhD thesis, Norwegian University of Science and Technology, Trondheim, Norway. 

Lederer, E. 1946. Chemistry and biochemistry of the scent glands of the beaver Castor fiber). Nature, 157, 231-232. 

The original structure of (— )-deoxynupharidine (15) was not correct and much of the earlier literature concerning these alkaloids contains erroneous structures. The compound has a l/ ,4/f,7/f,9a/ configuration, as indicated in Fig. 36.4 (Howard and Michael, 1986). Similar alkaloids have been isolated from the scent glands of the Canadian beaver. Castor fiber (Fig. 36.4). The oil of this gland or castoreum is used as a fixative in the perfumery industry. (— )-Deoxynu-pharidine (15) is one of the components of the complex mixture of compounds found in this oil. Although it is not clear. 

In internal reflection, at angles of incidence larger than the critical angle, electromagnetic radiation is totally reflected (attenuated total reflectance, ATR. see Section 16.2.2.4 and Fig. 5). This special ca.se is very important in analysis for two approaches. First, simple transportation of radiation within the fiber (or a waveguide). Second, in total reflection, an evane.scent field appears in which the electrical field vector decays exponentially in the optically less dense medium. Every change within the medium with lower refractive index influences the field vector coupled to the field in the optically denser medium. Therefore, the totally reflected radiation contains information about effects on the other side of the phase boundary (the medium with lower refractive index) [20], [144]. Various principles to interogate this effect are known and used in evanescent field sensors. 

Related C15 quinolizidines and one indolizidine alkaloid have also been found in the exudate from the scent glands of the Canadian beaver Castor fiber) (castoreum, previously used as a fixative in perfumery). For convenience, these animal alkaloids wiU be included in the present discussion. 

Headspace techniques have enabled the fragrance chemist to continue the search for new aroma chemicals and to recreate flower scents. For easily accessible regions, the most appropriate methodology is dynamic headspace using a polymeric adsorbent such as Tenax, if thermal desorption will be used, or Porpak Q, if solvent elution is to be used. This is preferable to SPME, which may require the use of more than one fiber. SPME can, however, provide a useful complement to dynamic headspace gas collection techniques for the capture of specific aroma chemicals. 

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