01673nas a2200253   4500008004100000022001400041245017700055210006900232260007700301300001400378490000700392520068600399653002001085653001901105653001801124653001801142653001301160100002201173700002501195700002801220700001501248700003001263856012601293       2014                        eng d  a0947-653900aVesicle structures from bolaamphiphilic biosurfactants: experimental and molecular dynamics simulation studies on the effect of unsaturation on sophorolipid self-assemblies0 aVesicle structures from bolaamphiphilic biosurfactants experimen  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcMAY  a6246-62500 v203 a<p>The formation of giant-vesicle-like structures by self-assembling linolenic acid sophorolipid (LNSL) molecules is revealed. Sophorolipids belong to the class of bolaamphiphilic glycolipid biosurfactants. Interestingly, the number of double bonds present in the hydrophobic core of sophorolipids is seen to have a great influence on the type of self-assembled structures formed. Dye encapsulation results establish the presence of an aqueous compartment inside the LNSL vesicles. Molecular dynamics simulation (MD) studies suggest the existence of two possible conformations of LNSLs inside the self-assembled structures and that LNSL molecules arrange in layered structures.</p>10abolaamphiphiles10aMD simulations10aSelf-assembly10asophorolipids10avesicles1 aDhasaiyan, Prabhu1 aPandey, Prithvi, Raj1 aVisaveliya, Nikunjkumar1 aRoy, Sudip1 aPrasad, Bhagavatula L. V.  uhttp://library.ncl.res.in/content/vesicle-structures-bolaamphiphilic-biosurfactants-experimental-and-molecular-dynamics-002621nas a2200169   4500008004100000022001400041245014800055210006900203260007100272300001400343490000800357520189700365100002002262700001502282700003402297856012002331       2016                        eng d  a1520-610600aValidation of force fields of rubber through glass-transition temperature calculation by microsecond atomic-scale molecular dynamics simulation0 aValidation of force fields of rubber through glasstransition tem  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a1367-13790 v1203 a<p>Microsecond atomic-scale molecular dynamics simulation has been employed to calculate the glass-transition temperature (T-g) of cis- and trans-1,4-polybutadiene (PB) and 1,4-polyisoprene (PI). Both all-atomistic and united-atom models have been simulated using force fields, already available in literature. The accuracy of these decade old force fields has been tested by comparing calculated glass-transition temperatures to the corresponding experimental values. T-g depicts the phase transition in elastomers and substantially affects various physical properties of polymers, and hence the reproducibility of T-g becomes very crucial from a thermodynamic point of view. Such validation using T-g also evaluates the ability of these force fields to be used for advanced materials like rubber nanocomposites, where T-g is greatly affected by the presence of fillers. We have calculated T-g for a total of eight systems, featuring all-atom and united-atom models of cis- and trans-PI and-PB, which are the major constituents of natural and synthetic rubber. Tuning and refinement of the force fields has also been done using quantum-chemical calculations to obtain desirable density and T-g. Thus, a set of properly validated force fields, capable of reproducing various macroscopic properties of rubber, has been provided. A novel polymer equilibration protocol, involving potential energy convergence as the equilibration criterion, has been proposed. We demonstrate that not only macroscopic polymer properties like density, thermal expansion coefficient, and T-g but also local structural characteristics like end-to-end distance (R) and radius of gyration (R-g) and mechanical properties like bulk modulus have also been equilibrated using our strategy. Complete decay of end-to-end vector autocorrelation function with time also supports proper equilibration using our strategy.</p>1 aSharma, Pragati1 aRoy, Sudip1 aKarimi-Varzaneh, Hossein, Ali  uhttp://library.ncl.res.in/content/validation-force-fields-rubber-through-glass-transition-temperature-calculation-0