Rotating-head model

Various theories have been introduced to explain the relative movemoit. Huxley proposed that the myosin head changed its orientation after binding to actin (die "rotating-head" model). According to the helix-coil transition, the normally o-helical coiled-coil structure "melts" to a random coil conformation, which implies a reduction in length. Movements of the myosin tails, as well as conformation changes of the actin have also been considered. It now seems clear, however, that the force production takes place in or very near the myosin heads [22]. Furthermore, among the three different states of myosin - empty actin site, ATP bound to the actin site and ADP-Pi boimd to die actin site - aU of which can... 

It is possible to classify all existing LT models in two families, depending on the origin of the laser beam from the rotating head of the LT or in the column holder with a mirror reflector in the rotating head. 

Laser Tracker with beam source in the rotating head. This model is typical of API and FARO and determination of their geometric errors has been systematized by Muralikrishnan et al. [3] and Hughes et al. [4]. According to the proposed model, calibration corrections are based on 15 parameters, each representing the influence of a particular geometric error in the overall error of the equipment ... 

It is well recognized that a head impact produces both translational and rotational motion as well as deformation of the skull. Resultant brain injury may occur from both absolute motion of the brain and its relative displacement with respect to the skull. At present, there are several physical parameters used in the evaluation of head injury, including translational and/or rotational acceleration levels of head impact, impact force, velocity and kinetic energy, impulse and impact duration, etc. These measures have been widely used for animal, human cadaver, and dummy experimental data to determine tolerable and survival thresholds for head impact in translation or rotation. Other parameters such as skull displacement and stresses, brain pressures and strains, as well as neck stretch/strain are usually related to analytical and experimental head model studies. 

Fig. 1. Model Spectra re-binned to CRIRES Resolution To demonstrate the potential for precise isotopic abundance determination two representative sample absorption spectra, normalized to unity, are shown. They result from a radiative transfer calculation using a hydrostatic MARCS model atmosphere for 3400 K. MARCS stands for Model Atmosphere in a Radiative Convective Scheme the methodology is described in detail e.g. in [1] and references therein. The models are calculated with a spectral bin size corresponding to a Doppler velocity of 1 They are re-binned to the nominal CRIRES resolution (3 p), which even for the slowest rotators is sufficient to resolve absorption lines. The spectral range covers ss of the CRIRES detector-array and has been centered at the band-head of a 29 Si16 O overtone transition at 4029 nm. In both spectra the band-head is clearly visible between the forest of well-separated low- and high-j transitions of the common isotope. The lower spectrum is based on the telluric ratio of the isotopes 28Si/29Si/30Si (92.23 4.67 3.10) whereas the upper spectrum, offset by 0.4 in y-direction, has been calculated for a ratio of 96.00 2.00 2.00.

Head et al. developed a PLS-based model VALIDATE [47] to scale the relative contributions of entropy and enthalpy to binding affinity for a variety of complexes whose crystal structures had been determined. Molecular mechanics were used to calculate several parameters most correlated with enthalpy of binding, while changes in surface area, number of rotatable bonds fixed upon binding and other parameters more related to the entropy of binding were also included in the model. Of interest was that the principal components of the model were dominated by two terms (AH and AS,... 

Molecular mechanics and dynamics studies of metal-nucleotide and metal-DNA interactions to date have been limited almost exclusively to modeling the interactions involving platinum-based anticancer drugs. As with metal-amino-acid complexes, there have been surprisingly few molecular mechanics studies of simple metal-nucleotide complexes that provide a means of deriving reliable force field parameters. A study of bis(purine)diamine-platinum(II) complexes successfully reproduced the structures of such complexes and demonstrated how steric factors influenced the barriers to rotation about the Pt(II)-N(purine) coordinate bonds and interconversion of the head-to-head (HTH) to head-to-tail (HTT) isomers (Fig. 12.4)[2011. In the process, force field parameters for the Pt(II)/nucleotide interactions were developed. A promising new approach involving the use of ab-initio calculations to calculate force constants has been applied to the interaction between Pt(II) and adenine[202]. 

Table 6 summarizes the characteristics of the modeled and experimental level sets for the nuclei that we have studied so far the modeled sets provided by Hoff are designated as Set A. Note, as an example, that the available experimental level information for Np consists of only 5 levels (including 3 rotational bands) up to 0.22 MeV in nuclear excitation, whereas the modeled Set A consists of 998 levels in the first 1.48 MeV and includes 94 rotational bands. Sets B through D were obtained by truncating the 998-level set just below selected band heads. In Fig. 7(a), curve A shows our calculated g/m ratio for 236Np production... 

---