Seawater can be used as mixing water for concrete with no steel reinforcement in some areas difficult access to fresh water. Diatoms such Phaeodactylum tricornutum are among the most abundant micro-organisms living seawater, and they could unavoidable when collecting seawater. In fact, diatoms provide bio-SiO2 bio-CaCO3 sources, namely amorphous nano-SiO2 crystallised nano-CaCO3, which benefici...

More than a century after its discovery the structure of the Pa(4+) ion in acidic aqueous solution has been investigated for the first time experimentally and by quantum chemistry. The combined results of EXAFS data and quantum chemically optimized structures suggest that the Pa(4+) aqua ion has an average of nine water molecules in its first hydration sphere at a mean Pa-O distance of 2.43 Å. ...

Isomer-specific 3-chloroacrylic acid dehalogenases function in the bacterial degradation of 1,3-dichloropropene, a compound used in agriculture to kill plant-parasitic nematodes. The crystal structure of the heterohexameric trans-3-chloroacrylic acid dehalogenase (CaaD) from Pseudomonas pavonaceae 170 inactivated by 3-bromopropiolate shows that Glu-52 in the alpha-subunit is positioned to funct...

It is shown that the projectiles ejected by discobolocysts in the single-celled Chry-sophyceaen alga Ochromonas tuberculatlls travel at speeds of up to 0.26 km/s, as fast as a bullet from a low power rifle. They may thus inflict damage to a would-be predator. Their Reynolds number is high..around 100, far from the low Reynolds numbers presumed typical of cellular evertts. Hydration of the mucop...

The molecular and crystal structure of 2'-O-Me (CGCGCG)2 has been determined using synchrotron radiation at near-atomic resolution (1.30 A), the highest resolution to date in the RNA field. The crystal structure is a half-turn A-type helix with some helical parameters deviating from canonical A-RNA, such as low base pair rise, elevated helical twist and inclination angles. In CG steps, inter-st...

Proton transport (PT) in bulk liquid water and within a thin water-filled carbon nanotube has been examined using ab initio path-integral molecular dynamics (PIMD). Barrierless proton transfer is observed in each case when quantum nuclear effects (QNEs) are accounted for. The key difference between the two systems is that in the nanotube facile PT is facilitated by a favorable pre-alignment of ...

the major hydraulic phase in all the calcium aluminate cements including ciment fondue is ca (caal2o4). once hydrated, it starts to form the hexagonal crystals of cah10 and c2ah8 that depending on the time and temperature of hydration convert to the cubic crystals of c3ah6 and ah3. the nature, sequence, crystallinity and microstructure of hydrated phases of commercial refractory calcium alumina...

Theoretical ab initio quantum mechanical charge field molecular dynamics (QMCF MD) has been applied in conjunction with experimental large angle X-ray scattering (LAXS) to study the structure and dynamics of the hydrated thiosulfate ion, S2O3(2-), in aqueous solution. The S-O and SC-ST bond distances have been determined to be 1.479(5) and 2.020(6) Å by LAXS and to be 1.478 and 2.017 Å by QMCF ...

Aqueous nitrate, NO3(-)(aq), was studied by 2D-IR, UV-IR, and UV-UV time-resolved spectroscopies in combination with molecular dynamics (MD) simulations with the purpose of determining the hydration dynamics around the anion. In water, the D3h symmetry of NO3(-) is broken, and the degeneracy of the asymmetric-stretch modes is lifted. This provides a very sensitive probe of the ion-water interac...

Properties of biomolecules are often investigated using Molecular Dynamics (MD) simulations whereby atoms and molecules interact for a period of time, thus revealing the time dependent behavior of the system. Whereas the atom positions of the starting structures for such MD runs are usually derived from X-ray crystallography or NMR experiments, properties such as charges or bonds are specified ...