Mixed-sector intermediate Hamiltonian Fock-space coupled cluster approach

An alternative formulation of the intermediate Hamiltonian Fock-space coupled cluster scheme developed before is presented. The methodological and computational advantages of the new formulation include the possibility of using a model space with determinants belonging to different Fock-space sectors. This extends the scope of application of the multireference coupled cluster method, and makes possible the use of quasiclosed shells (e.g., p2, d4) as reference states. Representative applications are described, including electron affinities of group-14 atoms, ionization potentials of group-15 elements, and ionization potentials and excitation energies of silver and gold. Excellent agreement with experiment (a few hundredths of an electronvolt) is obtained, with significant improvement (by a factor of 5-10 for p3 states) over Fock-space coupled cluster results. Many states not reachable by the Fock-space approach can now be studied.     

Reply to A Computational Evaluation of the Evidence for the Synthesis of 1,3‐Dimethylcyclobutadiene in Solid State and Aqueous Solution—Beyond the Experimental Reality

Following earlier reports on the photochemical synthesis of 1,3‐dimethylcyclobutadiene 8 , 10 in a protective host matrix, theoretical calculations for the formation of that adduct have been recently performed by Rzepa. 13 The author formulated criticisms based mainly on density functional theory calculations of ¹H NMR spectra. According to Rzepa the calculated spectra do not correspond with our measured spectra, which leads him to the conclusion that our interpretation is wrong, and that mainly cyclobutadiene has not been stabilized or even synthesized; we believe, however, that the initial model that Rzepa used for his calculations does not correspond to chemical reality or is at the very least a crude simplification of it, which implies that his calculations cannot match, in every point, our experimental spectra. Rzepa′s simplified models might be ‘reasonable’ from the theoretical point of view; however, in the case of assessment in the solid state, the theoretical setup does not force the system to preserve the confined stabilizing space defined by the crystalline matrix for encapsulated hosts in the solid state. Inversely, in the case of solution modeling, the theoretical setup is too rigid to properly assess the complex equilibria occurring in solution and to accurately determine the NMR spectra of exchanging species in solution. The inconsistency between our experimental results and the results of the theoretical models proposed by Rzepa is such that his conclusions are considered to be too far from experimental reality. Accurate modeling taking in account “reasonable” experimental details would be a worthwhile endeavor.     

High-order sliding-mode observation for linear systems with unknown inputs

A high-order sliding-mode observer is designed for linear systems with unknown inputs. The concepts of strong observability and strong detectability are studied and their relation with the relative degree of a plant is established. High-order sliding-mode-based observers for linear time-invariant systems with unknown inputs satisfying the condition of strong observability or strong detectability are developed.     

Surface grafting of a thermoplastic polyurethane with methacrylic acid by previous plasma surface activation and by ultraviolet irradiation to reduce cell adhesion

The material performance, in a biological environment, is mainly mediated by its surface properties and by the combination of chemical, physical, biological, and mechanical properties required, for a specific application.In this study, the surface of a thermoplastic polyurethane (TPU) material (Elastollan^®1180A50) was activated either by plasma or by ultra-violet (UV) irradiation. After surface activation, methacrylic acid (MAA) was linked to the surface of TPU in order to improve its reactivity and to reduce cell adhesion. Grafted surfaces were evaluated by X-ray photoelectron spectroscopy (XPS), by atomic force microscopy (AFM) and by contact angle measurements. Blood compatibility studies and cell adhesion tests with human bone marrow cells (HBMC) were also performed.If was found that UV grafting method led to better results than the plasma activation method, since cell adhesion was reduced when methacrylic acid was grafted to the TPU surface by UV.     

Quality assurance in forensic science

 Forensic examination results play an increasingly important role in bringing many criminal investigations to a successful conclusion. The quality of the results of examinations performed in forensic science laboratories has always been the concern of the individual forensic scientist. The interpretations and results are presented in court to non-experts. Therefore, it is essential to ensure and maintain the highest standards of achievements and accuracy in forensic science. Many factors are important contributors to quality assurance in forensic science. Some unique subjects affect not only the mode of inquiry but also the way in which information is presented to the court, i.e. exhibits collection and sample handling, investigation, examination techniques, report writing and court testimony.     

Cholesterol-containing liquid crystal dimers with ether linkages between the spacer and mesogenic units

Three series of chiral liquid crystalline dimers were investigated, having a cholesteryl and a cyanobiphenylyl, butoxybiphenylyl or hexyloxybiphenylyl group connected to a variable alkyl spacer through ether linkages. Their properties were compared with those of the corresponding ester derivatives. The phase behaviour of compounds with ether and ester linkages is comparable, showing N* and SmA phases. The melting points of the compounds with ether linkages are in the same range as those of the ester compounds, but the liquid crystal transition temperatures are lower. The smectic layer spacings and smectic ordering properties are also similar. The cyanobiphenylyl compounds have an interdigitated SmA layer structure, which shows a small odd-even effect with spacer parity. The alkoxybiphenylyl compounds have a monolayer SmA phase for short spacers and an intercalated SmA phase for longer spacers. The selective reflection wavelengths of the chiral nematic phase of the ether compounds are lower than those of the corresponding ester compounds. The transition from N* to interdigitated or monolayer SmA is accompanied by a strong increase in the selective reflection wavelength, indicative of an intermediate TGB phase. This is absent for the transition from N* to intercalated SmA.     

Diastereoselective synthesis of α,α′-disubstituted β-ketophosphonates derivatives as building blocks for automated syntheses

A convenient and efficient synthesis of α,α′-disubstituted β-ketophosphonic derivatives in good to excellent de’s and yields has been achieved by α-acylation followed by diastereoselective α-alkylation of chiral 5-membered cyclic phosphonamidates.