Thermal expansion of a rig

Summary We have estimated and measured the daily thermal expansion of an oceanographic platform. This has been found negligible as far as the calibration of a satellite altimeter is concerned.     

H and c NMR study of phosphopeptides : I—Acetylphosphoserine and acetylphosphothreonine

The ¹H and ¹³C NMR spectra of acetylserine, acetylphosphoserine and acetylphosphothreonine have been measured and completely analysed as a function of pD. For pD> 4 the NMR parameters are only slightly pD dependent. The second titration step of the phosphate group (pK₂ = 6.5) is much more difficult to detect in AcPSer (AcPTher) than in PSer (PThr). The ionization of the phosphate is of minor direct influence on the NMR parameters, their comparatively much larger changes in PSer (PThr) are due to conformational changes caused by the electrostatic interaction between the amino and phosphate group. The conformation in which the atoms H-C-Cβ-O-P form a planar W-type arrangement predominates at all pD values in the studied region from 4 to 14 in contrast to the non-cetylated phosphoamino acids in which its percentage passes a minimum at pD 8.     

Protein adsorption in static microsystems: effect of the surface to volume ratio

A numerical model for the adsorption kinetics of proteins on the walls of a microchannel has been developed using the finite element method (FEM) to address the coupling with diffusion phenomena in the restricted microchannel volume. Time evolutions of the concentration of one species are given, both in solution and on the microchannel walls. The model illustrates the adsorption limitation sometimes observed when the microdimensions of these systems induce a global depletion of the bulk solution. A new non-dimensional parameter is introduced to predict the final value of the coverage of any microsystem under static adsorption. A working curve and a criteria (h/K[Gamma](max) > 10) are provided in order to choose, for given adsorption characteristics, the value of the volume-to-surface ratio (i.e. the channel height h) avoiding depletion effects on the coverage (relative coverage greater than 90% of the theoretical one). Simulations were compared with confocal microscopy measurements of IgG antibody adsorption on the walls of a PET microchannel. The fit of the model to the experimental data show that the adsorption is under apparent kinetic control.     

Complete graph conjecture for inner-core electrons: homogeneous index case

The complete graph conjecture that encodes the inner-core electrons of atoms with principal quantum number n >or= 2 with complete graphs, and especially with odd complete graphs, is discussed. This conjecture is used to derive new values for the molecular connectivity and pseudoconnectivity basis indices of hydrogen-suppressed chemical pseudographs. For atoms with n = 2 the new values derived with this conjecture are coincident with the old ones. The modeling ability of the new homogeneous basis indices, and of the higher-order terms, is tested and compared with previous modeling studies, which are centered on basis indices that are either based on quantum concepts or partially based on this new conjecture for the inner-core electrons. Two similar algorithms have been proposed with this conjecture, and they parallel the two "quantum" algorithms put forward by molecular connectivity for atoms with n > 2. Nine properties of five classes of compounds have been tested: the molecular polarizabilities of a class of organic compounds, the dipole moment, molar refraction, boiling points, ionization energies, and parachor of a series of halomethanes, the lattice enthalpy of metal halides, the rates of hydrogen abstraction of chlorofluorocarbons, and the pED(50) of phenylalkylamines. The two tested algorithms based on the odd complete graph conjecture give rise to a highly interesting model of the nine properties, and three of them can even be modeled by the same set of basis indices. Interesting is the role of some basis indices all along the model.     

Longitudinal Relaxation of the Quaternary Carbons of Some Phosphine Oxides

Abstract

A detailed analysis of the longitudinal relaxation of the quaternary carbons of the phenyl groups in some diphenylphosphine oxides, and a comparison of the NMR data with X-Ray and theoretical results show that Cq(1) (cf. figure 1) relaxes mainly through an intramolecular DD mechanism and that dipolar interactions with atoms more than 3.5 Å away are unimportant. Residual mechanisms play a major role in the relaxation of Cq(2) and they are identified as CSA and/or SR mechanisms.     

Constantin Carathéodory and the axiomatic thermodynamics

The birth, raise, development and fortunes of a fundamental theory in thermodynamics, the axiomatic thermodynamics, a creation of Constantin Carathéodory, is thoroughly presented together with a summary of Carathéodory's biography. Axiomatic thermodynamics is centered around some interesting properties of Pfaffian differential equations, which are here introduced and used for some well-known cases in thermodynamics.     

Local effects in wind and wave fields in the Tyrrhenian sea

Summary A very sophisticated wave model has been applied to the western Mediterranean Sea. The results show the importance of local effects that had not been taken into account by the input atmospheric model. The need is stressed for the use of local models nested in the large-scale ones. Paper presented at the IV Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 22–24, 1987, Rome.     

Conformational study of phosphothreonine in aqueous solution. H and 13C NMR results

The 270 MHz ¹H and 22.6 MHz ¹³C NMR spectra of DL -phosphothreonine in D₂O have been measured and analysed as a function of pD. The trans-trans conformation of the fragment H-α? C-α? C-β? O? P predominates at all pD values. The C-β—O gauche contribution is notably larger for pD values in the range 7≤pD<10 than for acidic or more basic solutions which is in accordance with earlier results for phosphoserine (PSer).