Thomson Recombination

The classic treatment of carrier recombination can be related to the notion of the recombination time. The recombination time represents a combination of the carrier motion time (im), i.e. the time to get the carriers within capture radius (it is often assumed to be the Coulombic radius rc = e2/An o kT), and the elementary capture time (tc) for the ultimate recombination event (actual annihilation of charge carriers), tree1 = m1 -I Tc 1 (cf. Fig. 3). Following the traditional description of recombination processes in ionized gases, a Langevin-like [22] and Thomson-like [23] recombination can be defined if Tc xm and Tc Tm, respectively. In solid-states physics, these two cases have been distinguished 

The kinetic description of bimolecular reactions in condensed media, based on the solution of Smoluchowski 

As long as a2/AkT 1, / 1, and D(t) is a decreasing function of time. The Monte Carlo simulation study of dispersive transport in organic solids [38,39] has shown that Eq. (9) is applicable for o/kT ranging from 1 up to 20. However, a/kT= 1-5 may be too small for getting accurate estimations by means of Eqs. (8) and (9). 

The long-time balance between recombination and drift of carriers as expressed by the y/n ratio has been analyzed using a Monte Carlo simulation technique and shown to be independent of disorder [40]. Consequently, the Langevin formalism would be expected to obey recombination in disordered molecular systems as well. However, the time evolution of y is of crucial importance if the ultimate recombination event proceeds on the time scale comparable with that of carrier pair dissociation (Tc/Td l). The recombination rate constant becomes then capture—rather than diffusion-con-trolled, so that Thomson-like model would be more adequate than Langevin-type formalism for the description of the recombination process (cf. Sec. 5.4). 

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Several of these IFNs of mouse and human lymphocytes and fibroblasts are available commercially and have been best prepared in quantity by recombinant DNA procedures because they are produced in very small amounts by the cells. The commercial materials do not generally require further purification for their intended purposes. [Pestkas, Interferons and Interferon standards and general abbreviations. Methods Enzymol, Wiley Sons, 119 1986, ISBN 012182019X Lengyel, Biochemistry of interferons and their actions, Ann Bev Biochem 51 251-282 7982 De Maeyer and De Maeyer-Guignard, Interferons in The Cytokine Handbook, 3rd Edn, Thomson et al. Eds, pp. 491-516 7998 Academic Press, San Diego, ISBN 0126896623.]... 

Finally we must deal with perturbations not to pressureless matter but to baryons and photons. At early times, the universe is radiation dominated, and pr = p/3 for radiation. Before the epoch of recombination, the same Thomson scattering processes that keep the baryons ionized also keep the radiation tightly-coupled to the ions. The nuclei have pressure pb = (5kT/dmp)p [Pg.182]

Bebbington CR, Renner G, Thomson S, King D, Abrams D, Yarranton GT (1992), High level expression of a recombinant antibody from myeloma cells using a glutamine synthetase gene as an amplifiable selectable marker, Biotechnology 10 169-175. 

Nonlinear Thomson scattering can only be observed for the highest laser intensities, as shown in Fig. 11.7. As expected from the theory, when ao < 1, the nonlinear Thomson scattering vanishes and the collisional radiative processes from the thermal plasma prevail (Bremsstrahlung and radiative recombination). For ao > 1, these latter processes are still effective, as shown by the quadratic dependency on the electronic density of the plasma observed for 9 = 40°. However, this isotropic thermal emission remains less intense than the collimated nonlinear Thomson scattering emission and becomes detectable only at a large angle of observation (> 40°). 

Rothmund-Thomson (Recql 4) proteins. The genes that encode these proteins are altered in human syndromes of the same name. Patients with these diseases are predisposed to different forms of cancer. Cell lines derived from patients with these diseases exhibit chromosome instability and accumulate abnormal replication intermediates. When these helicase proteins are studied in vitro, they can unwind Holliday junction-like structures. A characteristic of many proteins involved in homologous recombination is that they can be visualized as forming subnuclear structures in cells in response to DNA damage. This can be directly visualized using immunofluorescence and the structures that are formed are called foci (see Section 23.8.2). 

The question arises what is the reason for the high field decrease of (jOg(F). One of them could be a transition from the Langevin to Thomson description of the volume recombination process (see Sec. 1.3). The recombination coefficient y in Eq. (319) cannot be longer expressed by the mobility of charge carriers [see Eq. (4)] and TrecAt follows a field increasing function of the mobility in the numerator of Eq. (319) or/and field-decreasing y. The Thomson-like recombination occurs whenever the capture time (tc) in the ultimate step of the recombination process becomes comparable with the dissociation time (tj) of an initial (Coulombically correlated) charge pair (CP). Such a recombination scheme, depicted in Fig. 172, allows PR to be expressed by Eq. (3). However, to complete this picture, the overall recombination probability should also... 

Newcomb et al. (1994) showed that B capsids also assemble in a cell-free system, using extracts prepared from Sf9 cells infected with recombinant baculoviruses encoding the HSV-1 capsid proteins. Similar to the observations by Tatman et al. (1994) and Thomson et al. (1994), the capsids formed in the cell-free system resembled native B capsids in morphology, sedimentation rate, protein compositions, and ability to react with HSV-Tspecific antibodies. Additional work by Newcomb et al. (1996) led to the identification of several assembly intermediates. In the cell-free system the first structures observed were partial capsids that consisted of an arclike segment of the external shell surrounding a region... 

It was suggested by Garrat and Thomson [16] as far back as 1934 that the initial step in the photochemistry of a metal carbonyl is the loss of a CO ligand. They measured the rate of the photodecomposition of Ni(CO)4 in both gas and solution phases, together with the thermal recombination of Ni(CO)3 with CO. These suggestions were initially thought of as radical when they were first published, but are now cornerstone features of this field and are today taken for granted. 

Shaked Z, Stewart T, Thomson J, Thomson JW, Tafaro T, and Hershenson S. Pharmaceutical Composition of Recombinant beta-Interferon and Formulation Processes. Patent 2001 00270799/EP-Bl. 

Three-Body Ion-Ion Recombination Thomson s Theory and Langevin Model... 

The three-body reaction (2.5.6) has third kinetic order oidy in the moderate pressure range, usually less than 1 atm, where it can be described by Thomson theory (Thomson, 1924). At higher pressures the process is limited by ion mobihty (see the discussion that follows. According to the Thomson theory, the act of recombination takes place if negative and positive ions approach each other closer than the critical distance ... 

The ion-ion recombination rate coefficients recalcidated to the second kinetic order, o, grow linearly with gas density. The growth is limited to moderate pressures by the framework of Thomson s theory, which requires the capture distance b to be less than the ion mean free path l/rioa) ... 

Comparison of the Thomson and Langevin models shows that recombination rate coefficients grow with pressme at moderate pressures and begin to decrease as... 

Numerically, the maximum recombination rate coefficient is about 1-3 10 cm /s. This coefficient decreases both with growth and with reduction of pressure from the near-atmospheric value (see Fig. 2-13). A generalized ion-ion recombination model, combining the Thomson and Langevin approaches for moderate and high pressures, was developed by Natanson(1959). 

Thomson and Langevin Models of Three-Body Ion-Ion Recombination. Comparing Thomson s and Langevin s models for the three-body ion-ion recombination, (2-93) and (2-97), find a typical value of pressure when the recombination rate coefficient is the highest. Specifically consider oxygen plasma at room gas temperature. 

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