Characteristics and performance of a "universal" membrane suitable for gas separation, pervaporation, and nanofiltration applications

The large diversity of membrane separation processes results in a different optimization of membrane materials and structures for each process. In this article, the extent to which a single membrane type can be used in gas separation, pervaporation, and nanofiltration has been investigated. Interpretation of transport and separation properties has led to the conclusion that the membrane SolSep 3360 is a multifunctional membrane fulfilling all requirements for the three separation processes. This can be achieved by keeping a good balance between the thickness of the top layer, sterical hindrance during transport, and the effect of hydrophobicity/hydrophilicity.     

Recovery and characterisation of hybrid firs (Abies alba x A. cephalonica, Abies albax A. numidica) embryogenic tissues after cryopreservation

Embryogenic tissues of hybrid firs were cryopreserved using a slow freezing protocol. The procedure involved preculture of tissues for 24, 48 or 72 h in media with different sorbitol concentrations (0.4 or 0.8 M) and addition of 5% (v/v) DMSO as cryoprotectant. The cell lines tested withstood cryopreservation, even though tissue regrowth after thawing was dependent on treatment and cell line. For cell line AN72, regrowth was 100% for all experimental conditions tested. With cell line AC78, regrowth was 100% except after shorter pretreatment durations, which produced 83% and 86% regrowth for 0.4 M and 0.8 M sorbitol pretreatment, respectively. Cell lines AC1 and AC4 were more sensitive to cryopreservation with 37.5 to 100% regrowth, respectively. Growth parameters evaluated 3 months after cryopreservation showed cell line and treatments effects. In most cases, cryopreservation had no negative effect on growth of tissues. Statistically significant differences in fresh mass accumulation were found for four samples out of 24 investigated, although growth increase of these tissues still reached 79.4-84.6%, compared with non-cryopreserved ones (100% increase). Maturation capacity and genetic fidelity were studied in tissues whose growth was not negatively influenced by cryopreservation. Maturation capacity of embryogenic tissues cryopreserved using the optimal protocol was comparable to that of non-frozen controls. RAPD analysis of 88 genomic regions per cell line did not reveal any changes in genetic fidelity of cryopreserved tissues compared to non-cryopreserved controls.     

180 degree unidirectional bond rotation in a biaryl lactone artificial molecular motor prototype

A bifunctional biaryl lactone has been synthesized that should be capable of iterative unidirectional aryl-aryl bond rotation via: (1) a diastereoselective lactone ring opening, (S)-1 to (P,S)-2 or (M,S)-2; (2) a chemoselective lactonization, (P,S)-2 or (M,S)-2 to (S)-3; and (3) a chemoselective hydrolysis, (S)-3 to (S)-1. Preliminary results of a racemic sample have indicated unidirectional 180 degrees rotation with very high directional selectivity per individual artificial molecular motor molecule through the first two steps of this sequence. [reaction: see text]     

Quantum Logic in Dagger Kernel Categories

This paper investigates quantum logic from the perspective of categorical logic, and starts from minimal assumptions, namely the existence of involutions/daggers and kernels. The resulting structures turn out to (1) encompass many examples of interest, such as categories of relations, partial injections, Hilbert spaces (also modulo phase), and Boolean algebras, and (2) have interesting categorical/logical/order-theoretic properties, in terms of kernel fibrations, such as existence of pullbacks, factorisation, orthomodularity, atomicity and completeness. For instance, the Sasaki hook and and-then connectives are obtained, as adjoints, via the existential-pullback adjunction between fibres.     

The pseudo-hyperplanes and homogeneous pseudo-embeddings of the generalized quadrangles of order (3, t)

In the paper “as reported by De Bruyn (Adv Geom, to appear)”, we introduced the notions of pseudo-hyperplane and pseudo-embedding of a point-line geometry and proved that every generalized quadrangle of order (s, t), 2 ≤ s < ∞, has faithful pseudo-embeddings. The present paper focuses on generalized quadrangles of order (3, t). Using the computer algebra system GAP and invoking some theoretical relationships between pseudo-hyperplanes and pseudo-embeddings obtained in “De Bruyn (Adv Geom, to appear)”, we are able to give a complete classification of all pseudo-hyperplanes of ${\mathcal{Q}}$ . We hereby find several new examples of tight sets of generalized quadrangles, as well as a complete classification of all 2-ovoids of ${\mathcal{Q}}$ . We use the classification of the pseudo-hyperplanes of ${\mathcal{Q}}$ to obtain a list of all homogeneous pseudo-embeddings of ${\mathcal{Q}}$ .     

Sonochemical hydrosilylation of 2-substituted cyclohexanones in the presence of Wilkinson complex

The sonochemical hydrosilylation of alkyl substituted cyclohexanones catalyzed by Rh (PPh3)3Cl is described. The application of ultrasonic irradiation during the reaction highly enhances the reaction rates and produces higher yields than those obtained in silent reactions. The stereoselectivity of the reaction has not been changed, the isomeric distribution, i.e. the cis/trans ratio of the 2-substituted cyclohexanols formed, is very close to those obtained in conventional stirred reactions.