Mechanical retting

Extensive research has been done on the mechanical separation of the bast from the core on kenaf. The U.S. Department on Agriculture sponsored a research in mechanical retting at the Mississippi State University [10] and with a private firm in Bakersfiled, California [11]. Chopped whole stock was used in a process involving a spiked cylinder and an airline cleaner [12]. Separation efficiencies of 42 to 48% were achieved. It was found that the moisture content was a critical factor in the separation efficiencies and, if controlled, the separation was cleaner and quicker. Fisher [11] used a modified cotton gin and found separation efficiencies of more than 90%. 

Prof, of Structural Mechanics (ret.), Sapienza Universitd di Roma... 

Wenzel, A., Grimm, C., Samardzija, M., Reme, C.E., 2005. Molecular mechanisms of light-induced photoreceptor apoptosis and neuroprotection for retinal degeneration. Prog Ret Eye Res. 24, 275-306. 

DHT may occur over different tryptophan forms in proteins as they quite often have inhomogeneously broadened electronic spectra [31]. A very interesting case of DHT is described between two indole rings in bichromophoric solutes tryptophan dipeptide [32]. Such directed transport allows to correctly interpret spectral properties of dipeptide and other multichromophoric solutes. The theory of inductive-RET in solutions with inhomogeneous spectral broadening is given in Ref. [33]. In more detail, DHT mechanism will be explained in Sect. 2.2 (vide infra). 

Dispersion in packed tubes with wall effects was part of the CFD study by Magnico (2003), for N — 5.96 and N — 7.8, so the author was able to focus on mass transfer mechanisms near the tube wall. After establishing a steady-state flow, a Lagrangian approach was used in which particles were followed along the trajectories, with molecular diffusion suppressed, to single out the connection between flow and radial mass transport. The results showed the ratio of longitudinal to transverse dispersion coefficients to be smaller than in the literature, which may have been connected to the wall effects. The flow structure near the wall was probed by the tracer technique, and it was observed that there was a boundary layer near the wall of width about Jp/4 (at Ret — 7) in which there was no radial velocity component, so that mass transfer across the layer... 

Fig. 36 Sensing mechanism of the TBA probe for the detection of Pb2+ and Hg2+ through enhanced RET-type quenching. (Reprinted with permission from [212]. Copyright 2009 American Chemical Society)...

The mechanisms of resonance energy transfer (RET) between a donor and an acceptor have been described in Section 4.6.3. The aim of this chapter is to present further aspects of RET and its applications for probing matter or living systems. RET is particularly widely used to determine distances in biomolecules and supra-molecular associations and assemblies. 

Tezel, G. (2006). Oxidative stress in glaucomatous neurodegeneration Mechanisms and consequences. Prog. Ret. Eye Res. 25, 490-513. 

About 50% of patients with tardive dystonia have ret-rocollis if the trunk is involved, most of the patients have back-arching opisthotonos. Five such patients experienced relief with a custom-made mechanical device that delivers constant contact to the occiput and shoulders (336). 

Many of the addition mart ions listed in Ret-iew Table 1 tako pUco by an eiecirophiUc addition meeixamsm. The electrophile can be H", X, Hr. but the basic process is the same. The remainirg addition reactionji in Review Table 1 occur by other mechanisms. 

For aliphatic electrophihc substitution, we can distinguish at least four possible major mechanisms, which we call Sgl, Se2 (front), Se2 (back), and Sei. The Sgl is unimolecular the other three are bimolecular. It is noted that the term SeAt has been proposed to represent electrophilic aromatic substitution, so that the term Se2 refers exclusively to electrophihc substitutions where a steric course is possible. To describe the steric course of an aliphatic substitution reaction, the suffixes ret and inv were proposed, referring to retention and inversion of conhguration, respectively. 

Fig. 9. Behavior of relaxation current components in application of a potential step for the study of adsorption of an intermediate in a continuous Faradaic reaction (example. O2 evolution on nickel oxide, from ReT. 124 Charging current, i(< Faradaic current, if-, and total current, iV. Calculated for reaction mechanism (4) and (5) with = 0.01, k-4 = 0.1, and k, = 0.001 the charge for monolayer formation is 100 fiC cm. ...

A recent study of the mechanism of Ziegler-Natta catal rets has been published by Rodriguez and coworkers 120). These authors showed by dectron microscopy that active sites are found mainly at growth spirals, on lateral surfaces, and on surface defects of the hexagonal a-TiClg crystal platelets. The active site has been proposed to be linked to a surface titanium atom with two chlorine vacancies of the otherwise octahedrally coordinated titanium. In a schematic two dimensional representation the proposed mechanism for propylene polymerization is as follows 120) ... 

Figure II. Dynamic analysts of the phntnchtomism and (he photodcgradzlion of spirolindulLms-benaopyran] 4 in toluene under COniinutKlS irradiation at 366 nm. The relaxation kindles were ret ended in the dark. The curves shown as full lines correspond 10 the simulation of the mechanism using the lilted values of the parameters. The three kmelic runs (a), (b). and (c> vre mottled at 601 (A) and 366 nm (ftI and correspond 10 the following experimental conditions a) A = X.94 x I0" mol liter"1, tfy = L.22 10" mol liter"1 s"1, 320 i (b) [A q = 542 x tl-5 mol liter-1,...

Umcda. K., Yano, T. and 1 lira no, M. (1988). Fy ret hroid-resi stance mechanism in German Cockroach. BkilleHa germanica rOrthoplcra Biattidae). Appi. Entanud. Zoat. 23, 373-380. 

This enhancement is ascribed to both the activation of H2O to OHads on Ru and a decrease in CO binding energy when Ru is added to the surface due to electronic effects of alloying (bifunctional mechanism). Raising the fuel cell temperature above 160°C can decrease the CO coverage remarkably. For a reformate gas containing CO, Pt-Ru electrodes are commonly used, and a number of other Pt-alloys such as Pt-Mo,P Pt-Sn,[ °] Pt-Rh,[ l and Pt-Ret have been studied for the HOR reaction. 

Hemp is retted in water tanks in a manner similar to flax, after which the stalks are laid out to dry. The fibres are then separated either manually or mechanically by passing through fluted rollers which crush the woody tissues. At this state the hemp is softened by beating with a softwood mallet on a flat stone or a hard floor. The same effect can also be achieved when a heavy millstone, usually operated by water power, rolls over the fibres for 3 or 4 hours. Finally the fibres, which tend to stick together, are separated by combing. 

Figure 7.1. Mechanism of suppression for the cation self-regenerating suppressor. fT MSA = Methane-sulfonic acid. From Ret [3] with permission.

Other oncogenic mechanisms of RTK activation include mutations in the kinase domain inducing conformational shift of the activation loop and a subsequent constitutive activation as well as constitutive dimerization as the result of a mutation in the extracellular domain of the RTK. Both modes of activation have been observed in germline mutations of the receptor tyrosine kinase Ret, leading to heritable tumor syndromes. 

Receptor coupling, 287 Receptor diseases, 79 Receptor history, 79 Receptor regulation, 79 Receptors, 79, 287, 305, 333 Receptor structure, 79 Receptor tyrosine kinase, 261 Recombinant human receptors, 125 Release mechanism, 65 RET, 261 RGS proteins, 333 Rhinovirus, 291... 

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