Passive role

Fig. 30. — Packing arrangement of 4-fold antiparallel double helices of potassium hyaluronate (32). (a) Stereo view of a unit cell approximately normal to the line of separation of the two helices. The two chains in each duplex, drawn in open and filled bonds for distinction, are linked by not only direct hydrogen bonds, but also water bridges. Inter double-helix hydrogen bonds are mediated between hydroxymethyl and iV-acetyl groups. Potassium ions (crossed circles) at special positions have only a passive role in the association of hyaluronate chains.

Artificial organs that perform the physical and biochemical functions of the heart, hver, pancreas, or lung are one class of organ replacements. A rather different target of opportunity is the development of biologieal materials that play a more passive role in the body for example,... 

Another possible reason for public interest in herbal medications is that they provide some autonomy from medical professionals. Multiple factors contribute to a person s satisfaction with medical care (Siahpush et al. 1999 Sixma et al. 1998 Kaptchuk and Eisenberg 1998). One cause of dissatisfaction results from the traditionally passive role of the patient. Independent of its efficacy, alternative medicine provides an individual with a greater range of explanations and treatment options for their illnesses. The psychological appeal of more options is sufficient to draw individuals to consult alternative medicine, especially in cases where modern medicine has not been effective. 

Another naturally occurring ribozyme which catalyzes phosphodiester transfer reactions is the hairpin ribozyme. The hairpin ribozyme has been the subject of a number of excellent review articles [24,25]. Several independent studies performed recently have indicated that the hairpin ribozyme has an interesting feature which distinguishes it from the aforementioned ribozymes mechanistically While the HHR, the group I intron, the HDV ribozyme and many other ribozymes that we are going to meet in this review are metalloenzymes and require divalent metal ions in their active sites for functional group activation, divalent metals ions only play a passive role (they are mainly required for cor-... 

Protective groups play a passive role in synthesis. Each operation of introduction and removal of a protective group adds steps to the synthetic sequence. It is thus desirable to minimize the number of such operations. Fortunately, the methods for protective group introduction and removal have been highly developed, and the yields are usually excellent. 

Originally, it was assumed that the Py-complex only played a passive role in the functional cycle of the G-proteins. It soon became apparent, however, that the Py-complex, in addition to binding to the a-subimit, also carries out other functions and interacts specifically with corresponding effector molecules (review article Neer, 1995). Tlie Py-complex must be assigned its own regulatory function, it takes part itself in the propagation and termination of signal transmission. 

Rather phase-insensitive Norrish II photoproduct ratios are reported from irradiation of p-chloroacetophenones with a-cyclobutyl, a-cyclopentyl, a-cycloheptyl, a-cyclooctyl, and a-norbonyl groups [282], In each case, the E/C and cyclobutanol photoproduct ratios are nearly the same in neat crystals as measured in benzene or acetonitrile solutions. On this basis, we conclude that the reaction cavity plays a passive role in directing the shape changes of these hydroxy-1,4-biradicals. As long as the initial ketone conformation within the cavity permits -/-hydrogen abstraction (and these ketones may be able to explore many conformations even within their triplet excited state lifetime), the cavity free volume and flexibility allow intramolecular constraints to mandate product yields. 

CHLORIDE (Biological Aspects). Sodium chloride, potassium chloride, and other chloride salts, when ingested by animals from feedstuffs and humans from various food substances, reduce to a consideration of the cation involved (Na", K h. etc.) and the Cl (chloride) ion. Generally, in terms of animal and human nutrition, more research has been conducted and more is known about the role of cations in metabolism than that of the chloride ion. Some physiologists and nutritionists in the pasi have described chloride as playing a "passive role" in maintaining the body s ionic and fluid balance. With exception of the chloride shift" in venous blood, the movements of chloride have usually been considered secondary to those of the cations. 

Tn the Rohr model of the hydrogen atom, the proton is a massive positive point charge about which the electron moves. By placing quantum mechanical conditions upon an otherwise classical planetary motion of the electron, Bohr explained the lines observed in optical spectra as transitions between discrete quantum mechanical energy states. Except for hvperfine splitting, which is a minute decomposition of spectrum lines into a group of closely spaced lines, the proton plays a passive role in the mechanics of the hydrogen atom, It simply provides the attractive central force field for the electron,... 

The retention mechanism is not yet fully understood. The solvophobic theory does not account for any interaction in the stationary phase, which plays a passive role. The partition mechanism as described by Dill and Dorsey (27) is generally accepted. The most relevant feature is the linear plot of In k versus carbon number in a homologous series (Fig. 10), which is similar to what is observed in isothermal gas-liquid chromatography. Retention is governed mainly by hydro-... 

This advice does not mean a passive role on your part is best. You are not required to simply sit back. You have a need to talk about the problems with others and also to express your feelings with those immediately involved. It is essential that you handle the problem openly. You should remain determined to stay in charge of defining your own role in future relationships. 

Glass in the form of the optical fibre plays an unrivalled passive role in communications technology. Many messages, in the form of a string of light pulses generated by solid state (e.g. GaAs- or InP-based) lasers, are multiplexed... 

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