From Lucid to TransLucid: Iteration, Dataflow, Intensional and Cartesian Programming

We present the development of the Lucid language from the Original Lucid of the mid-1970s to the TransLucid of today. Each successive version of the language has been a generalisation of previous languages, but with a further understanding of the problems at hand. The Original Lucid (1976), originally designed for purposes of formal verification, was used to formalise the iteration in while-loop programs. The pLucid language (1982) was used to describe dataflow networks. Indexical Lucid (1987) was introduced for intensional programming, in which the semantics of a variable was understood as a function from a universe of possible worlds to ordinary values. With TransLucid, and the use of contexts as firstclass values, programming can be understood in a Cartesian framework.      

Viscometric and volumetric behaviour of binary mixtures of sulfolane and N-methylpyrrolidone with monoethanolamine and diethanolamine in the range 303–373 K

Capillary viscometry was used to determine the kinematic viscosity of the binary systems composed of N-methylpyrrolidone + monoethanolamine and N-methylpyrrolidone + diethanolamine throughout the concentration range, at eight different temperatures in the range 303.15–373.15 K. Pure component values of viscosity were also determined in the temperature range 303.15–423.15 K. Using a rolling ball viscometer the absolute viscosity was obtained for the binary systems composed of tetramethylene sulfone (sulfolane) + monoethanolamine and tetramethylene sulfone + diethanolamine, throughout the concentration range, at three different temperatures in the range 303.15–373.15 K. Density results were obtained using a vibrating-tube densimeter for the four pure components and the four binary systems studied, in the same temperature range and the whole concentration range for the binary systems as the viscosity measurements.

The experimental viscosity results for the four pure solvents cover a broader temperature range than previously reported by other workers. The experimental results of viscosity for both pure and binary systems show a decrease with increasing temperature as expected. In the case of the binary systems the change of viscosity with concentration for the two sets of mixtures with N-methylpyrrolidone is very large in the range of 303.15–353.15 K, whereas it is small in the range 363.15–373.15 K. The observed behaviour of the change of viscosity with concentration for sulfolane with monoethanolamine is different from that shown by sulfolane with diethanolamine, at 303.15 and 323.15 K; the first system shows a minimum viscosity point in the sulfolane-rich region whereas at 373.15 K it shows values of viscosity greater than that of the pure components in the whole range of concentration; and the second system shows large variations of viscosity at low sulfolane concentration, at 303.15 and 323.15 K; whereas at 373.15 K the viscosity values change smoothly between those for the two pure components.

From the density results, molar excess volumes were derived, which were correlated using the Redlich–Kister equation; the final expression includes the functionality with both concentration and temperature.     

Self-assembly of ligands designed for the building of a new type of [2 x 2] metallic grid. anion encapsulation and diffusion NMR spectroscopy

The ligands 4,6-bis(pyrazol-1-yl)pyrimidine (bpzpm), 4,6-bis(3,5-dimethylpyrazol-1-yl)pyrimidine (bpz(*)pm), 4,6-bis(4-methylpyrazol-1-yl)pyrimidine (Mebpzpm), and 3,6-bis(3,5-dimethylpyrazol-1-yl)pyridazine (ppdMe) were synthesized and were made to react with Cu(I) centers in the presence of different counteranions. Different [2 x 2] metallic grids were obtained. With ligands bpzpm, bpz*pm, and Mebpzpm, a new type of grid was obtained where the facing ligands were divergent and two counteranions (BF(4-) or PF(6-)) were hosted in the resulting cavities and exhibit C-H...F and anion...pi interactions in the solid state. The presence of methyl groups on the pyrazolyl rings induced several distortions in the structure. In complexes with the ligand ppdMe, there were found two groups of parallel ligands in the grid, and the cavities generated were smaller. The counteranions were situated outside the grid, and the facing ligands exhibited aromatic pi-pi stacking interactions. Anion-pi interactions involving the pyridazine ring were found. The behavior in solution of the new derivatives with a special emphasis on the cation-anion interactions was studied by UV-vis and NMR spectroscopy. Diffusion NMR experiments performed for some complexes allowed us to conclude that weak cation-anion interactions exist in solution, with the counteranions undergoing fast exchange on the diffusion time scale between the free and ion-paired states.     

Polarization behavior of polystyrene particles under direct current and low‐frequency (<1 kHz) electric fields in dielectrophoretic systems

The relative polarization behavior of micron and submicron polystyrene particles was investigated under direct current and very low frequency (<1 kHz) alternating current electric fields. Relative polarization of particles with respect to the suspending medium is expressed in terms of the Clausius–Mossotti factor, a parameter of crucial importance in dielectrophoretic‐based operations. Particle relative polarization was studied by employing insulator‐based dielectrophoretic (iDEP) devices. The effects of particle size, medium conductivity, and frequency (10–1000 Hz) of the applied electric potential on particle response were assessed through experiments and mathematical modeling with COMSOL Multiphysics^®. Particles of different sizes (100–1000 nm diameters) were introduced into iDEP devices fabricated from polydimethylsiloxane (PDMS) and their dielectrophoretic responses under direct and alternating current electric fields were recorded and analyzed in the form of images and videos. The results illustrated that particle polarizability and dielectrophoretic response depend greatly on particle size and the frequency of the electric field. Small particles tend to exhibit positive DEP at higher frequencies (200–1000 Hz), while large particles exhibit negative DEP at lower frequencies (20–200 Hz). These differences in relative polarization can be used for the design of iDEP‐based separations and analysis of particle mixtures.     

Dielectrophoresis for the manipulation of nanobioparticles

Dielectrophoresis (DEP) is a nondestructive electrokinetic mechanism with great potential for the manipulation of bioparticles. DEP is the movement of particles induced by polarization effects in nonuniform electric fields. Since the 1960s, this technique has been successfully used for the manipulation of microbioparticles, such as microorganisms. Moreover, due to the advances in microfabrication techniques, that allowed progressively smaller microstructures to be constructed, DEP can now be used for the manipulation of nanobioparticles. The first research studies on the DEP of nanobioparticles started in the 1990s. Since then, many research groups have carried out outstanding work with DEP of nanobioparticles such as macromolecules, virus, and spores. However, the need of a critical report that integrates these findings is evident. The aim of the present review is to depict the state-of-the-art on the use of DEP for the separation of nanobioparticles and the potential trends of novel applications of this technique. This review compiles and analyzes the significant findings obtained by many researchers. This publication is intended to provide the reader with state-of-the-art information on many research studies focused on DEP to handle nanobioparticles.     

Effect of beta-lactoglobulin hydrolysis with thermolysin under denaturing temperatures on the release of bioactive peptides

In this study, bovine beta-lactoglobulin A (beta-Lg A) was hydrolysed with thermolysin under non-denaturing and heat-denaturing conditions. The peptides released during hydrolysis were identified by HPLC-MS/MS. A total of 25 peptides were identified in the hydrolysate obtained at 37 degrees C for 5 min. Some of these peptides survived to further proteolysis even at higher incubation temperatures. Furthermore, novel cleavage sites localised in the most buried zones of beta-Lg and available for thermolysin were recognised when the incubation temperature increased in the range between 60 and 80 degrees C. Three new peptides, LDA, LKPTPEGD, and LQKW, appeared after 30 min hydrolysis at these incubation temperatures, but they were not identified in the 30-min hydrolysates obtained at 37 and 50 degrees C. Of special interest was the peptide LQKW, corresponding to the fragment f(58-61) that had been previously described as a potent angiotensin-converting enzyme-inhibitor (IC50 value of 34.7 microM).     

An activated equivalent of lactide toward organocatalytic ring-opening polymerization

The alpha-lactone equivalent lacOCA exhibits remarkable reactivity compared with lactide in nucleophile-catalyzed ROP. PLAs of controlled molecular weights and narrow polydispersities are typically obtained under mild conditions using DMAP and various protic initiators.     

Walking metals in d8···d8 hetero-bimetallic complexes: an original dynamic phenomenon

In the course of our investigations on polymetallic complexes derived from 1,3-bis(thiophosphinoyl)indene (Ind(Ph(2)P=S)(2)), we observed original fluxional behavior and report herein a joint experimental/computational study of this dynamic process. Starting from the indenylidene chloropalladate species [Pd{Ind(Ph(2) P=S)(2)}Cl](-) (1), the new Pd(II)···Rh(I) hetero-bimetallic pincer complex [PdCl{Ind(Ph(2) P=S)(2)}Rh(nbd)] (2; nbd=2,5-norbornadiene) was prepared. X-ray crystallography and DFT calculations substantiate the presence of a d(8)···d(8) interaction. According to multinuclear variable-temperature NMR spectroscopic experiments, the pendant {Rh(nbd)} fragment of 2 readily shifts in solution at room temperature between the two edges of the SCS tridentate ligand. To assess the role of the pincer-based polymetallic structure on this fluxional behavior, the related monometallic Rh complex [Rh{IndH(Ph(2) P=S)(2)}(nbd)] (3) was prepared. No evidence for a metal shift was observed in that case, even at high temperature, thus indicating that inplane pincer coordination to the Pd center plays a crucial role. The previously described Pd(II)···Ir(I) bimetallic complex 4 exhibited fluxional behavior in solution, but with a significantly higher activation barrier than 2. This finding demonstrates the generality of this metal-shift process and the strong influence of the involved metal centers on the associated activation barrier. DFT calculations were performed to shed light onto the mechanism of such metal-shift processes and to identify the factors that influence the associated activation barriers. Significantly different pathways were found for bimetallic complexes 2 and 4 on one hand and the monometallic complex 3 on the other hand. The corresponding activation barriers predicted computationally are in very good agreement with the experimental observations.