Solvent free models

Cooke IR, Deserno M. Solvent-free model for self-assembling fluid bilayer membranes stabilization of the fluid phase based on broad attractive tail potentials. J. Chem. Phys. 2005 123 224710. 

To parameterize the polymersome model, the identification of the virial coefficients, vaij and wapv is driven by the requirement that the amphiphiles described by (10) and (12) should create a stable bilayer with given material properties. Assuming that the hydrophobic interior should be in a melt state, the coefficients vaa and Waaa are determined such that (12) enforces the A-blocks to create a melt in equilibrium with its vapor which, in a solvent free model, represents the surrounding water. It can be shown, from (12), that the equation of state of such a homogeneous melt, within mean-field approximation, is [138]... 

Among the different available preparation techniques, direct formation of planar lipid bilayers from unilamellar vesicles is the most widespread method for obtaining solvent-free model membranes providing the required platform to study adsorption of proteins. 

Wang ZJ, Desemo M (2010) A systematically coarse-grained solvent-free model for quantitative phospholipid bilayer simulation. J Phys Chem B 114(34) 11207-11220... 

Cooke, I. R., and Desemo, M. 2005. Solvent-free model for self-assembling fluid bilayer membranes Stabilization of the fluid phase based on broad attractive tail potentials. J. Chem. Phys. 123 224710. de Gennes, P. G. 1980. Conformations of polymers attached to an interface. Macromolecules 13 1069. Espanol, R, and Warren, P. 1995. Statistical mechanics of dissipative particle dynamics. Europhys. Lett. 30 ... 

The thermodynamic integration scheme can be appUed to different models including coarse-grained, partide-based models of amphiphihc systems and membranes [133, 134] (e.g., soft DPD-models [135-137], Lennard-Jones models [138,139], or solvent-free models [140-142] of membranes) as well as field-theoretic representations [28]. It can be implemented in Monte Carlo or molecular dynamic simulations, as well as SCMF simulations [40-42, 86], field-theoretic simulations [28], and external potential dynamics [27, 63, 64] or dynamic density functional theory [143, 144]. 

Alternatively, solvent-free models able to describe large-scale membrane remodelling processes using MD simulations have been developed by several groups.= " " ... 

Solvent-free models, triangulated surfaces and other discretized curvature models have the disadvantage that they do not contain a solvent, and therefore do not describe the hydrodynamic behavior correctly. However, this apparent disadvantage can be turned into an advantage by combining these models with a mesoscopic hydrodynamics technique. This approach has been employed for dynamically triangulated surfaces [37,180] and for meshless membrane models in combination with MPC [188], as well as for fixed membrane triangulations in combination with both MPC [187] and the LB method [189]. 

The final class of methods that we shall consider for calculating the electrostatic compone of the solvation free energy are based upon the Poisson or the Poisson-Boltzmann equatior Ihese methods have been particularly useful for investigating the electrostatic properties biological macromolecules such as proteins and DNA. The solute is treated as a body of co stant low dielectric (usually between 2 and 4), and the solvent is modelled as a continuum high dielectric. The Poisson equation relates the variation in the potential (f> within a mediu of uniform dielectric constant e to the charge density p ... 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

T Ichiye. Solvent free energy curves for electron transfer A non-lmear solvent response model. J Chem Phys 104 7561-7571, 1996. 

In the preceding solvent extraction models, it was assumed that the phase flow rates L and G remained constant, which is consistent with a low degree of solute transfer relative to the total phase flow rate. For the case of gas absorption, normally the liquid flow is fairly constant and Lq is approximately equal to Li but often the gas flow can change quite substantially, such that Gq no longer equals Gj. For highly concentrated gas phase systems, it is therefore often preferable to define flow rates, L and G, on a solute-free mass basis and to express concentrations X and Y as mass ratio concentrations. This system of concentration units is used in the simulation example AMMONAB. 

Oxidation of these model sulfur compounds was studied without solvent to investigate the chemical structure of the products using S K-edge XANES. A solvent free tri-phase (organic/ H202aq./catalyst) was used under the described conditions. Figure 1 shows the XANES spectra from the organic and aqueous phases as well as reference materials. The thiophene oxidized to thiophene-sesquioxide [3a,4,7,7a-tetrahydro-4,7-epithiobenzo[b]-thiophene 1,1.8-trioxide ] first.. The sesquioxide solid precipitated from the solvent free reaction mixture and was identified by NMR, IR and C,H,S elemental analytical. The sesquioxide oxidized to sulfate. 2-MT and 2,5 DMT also oxidized to... 

Outer sphere relaxation arises from the dipolar intermolecular interaction between the water proton nuclear spins and the gadolinium electron spin whose fluctuations are governed by random translational motion of the molecules (106). The outer sphere relaxation rate depends on several parameters, such as the closest approach of the solvent water protons and the Gdm complex, their relative diffusion coefficient, and the electron spin relaxation rate (107-109). Freed and others (110-112) developed an analytical expression for the outer sphere longitudinal relaxation rate, (l/Ti)os, for the simplest case of a force-free model. The force-free model is only a rough approximation for the interaction of outer sphere water molecules with Gdm complexes. 

Lattanzi screened various amino alcoUiol derived thioureas in the enantioselec-tive Morita-Baylis-HiUman model reaction between cyclohexenecarbaldehyde and 2-cyclohexene-l-one (MBH adduct 1 Scheme 6.151) under solvent-free... 

According to this theoretical treatment, the slope of the plots of In k versus the solvent concentration, [3]m, can be employed to derive the contact area associated with the peptide-nonpolar ligand interaction. The retention and elution of a peptide in RPC can then be treated as a series of microequilibriums between the different components of the system, as represented by eq 6. The stoichiometric solvent displacement model addresses a set of considerations analogous to that of the preferential interaction model, but from a different empirical perspective. Thus, the affinity of the organic solvent for the free peptide P, in the mobile phase can be represented as follows ... 

Figure 56)155. Compounds investigated included three forms of tetramesityldisilene the solvent-free form 69156, the toluene adduct 69-C7Hs157 and the tetrahydrofuran solvate 69 THF158. Also studied were a second tetraaryldisilene (70)159 dialkyldiaryl-substituted disilene, 71160, and the only tetraalkyldisilene known to be stable as a solid, 72161. Three silyl-substituted disilenes, 73, 74 and 75, were also investigated162,163. To assist in the interpretation of the experimental results, ab initio molecular orbital calculations of the 29Si chemical shift tensors were carried out for model disilene molecules. 

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