On Safe Folding

In [3] a general fold operation has been introduced for definite programs wrt computed answer substitution semantics. It differs from the fold operation defined by Tamaki and Sato in [26,25] because its application does not depend on the transformation history. This paper extends the results in [3] by giving a more powerful sufficient condition for the preservation of computed answer substitutions. Such a condition is meant to deal with the critical case when the atom introduced by folding depends on the clause to which the fold applies. The condition compares the dependency degree between the fonding atom and the folded clause, with the semantic delay between the folding atom and the ones to be folded. The result is also extended to a more general replacement operation, by showing that it can be decomposed into a sequence of definition, general folding and unfolding operations

Acceptability with general orderings

We present a new approach to termination analysis of logic programs. The essence of the approach is that we make use of general orderings (instead of level mappings), like it is done in transformational approaches to logic program termination analysis, but we apply these orderings directly to the logic program and not to the term-rewrite system obtained through some transformation. We define some variants of acceptability, based on general orderings, and show how they are equivalent to LD-termination. We develop a demand driven, constraint-based approach to verify these acceptability-variants. The advantage of the approach over standard acceptability is that in some cases, where complex level mappings are needed, fairly simple orderings may be easily generated. The advantage over transformational approaches is that it avoids the transformation step all together. {\bf Keywords:} termination analysis, acceptability, orderings.Comment: To appear in "Computational Logic: From Logic Programming into the Future

The Effects of an Acute Bout of Self-Myofascial Release on the Physiological Parameters of Running

Please refer to the pdf version of the abstract located adjacent to the title

Bis-rhodamines bridged with a diazoketone linker: synthesis, structure, and photolysis

Two fluorophores bound with a short photoreactive bridge are fascinating structures and remained unexplored. To investigate the synthesis and photolysis of such dyes, we linked two rhodamine dyes via a diazoketone bridge (−COCN2−) attached to position 5′ or 6′ of the pendant phenyl rings. For that, the mixture of 5′- or 6′-bromo derivatives of the parent dye was prepared, transformed into 1,2-diarylacetylenes, hydrated to 1,2-diarylethanones, and converted to diazoketones Ar1COCN2Ar2. The high performance liquid chromatography (HPLC) separation gave four individual regioisomers of Ar1COCN2Ar2. Photolysis of the model compound─C6H5COCN2C6H5─in aqueous acetonitrile at pH 7.3 and under irradiation with 365 nm light provided diphenylacetic acid amide (Wolff rearrangement). However, under the same conditions, Ar1COCN2Ar2 gave mainly α-diketones Ar1COCOAr2. The migration ability of the very bulky dye residues was low, and the Wolff rearrangement did not occur. We observed only moderate fluorescence increase, which may be explained by the insufficient quenching ability of diazoketone bridge (−COCN2−) and its transformation into another (weaker) quencher, 1,2-diarylethane-1,2-dione

Thiophene-based helicenes : eclectic scaffolds in organometallic chemistry

Helicenes are ortho-annulated polycyclic aromatic compounds, endowed with an inherently chiral \u3c0-conjugated system that are intensively studied in different areas of science.1 Among helicenes, thiophene-based helicenes are emerging as an intriguing and promising class of screw-shaped structures, thanks to the presence of the thiophene rings, which confer peculiar chemical, structural, and electronic features.2 For several years, we have been interested in the synthesis and functionalization of tetrathia[7]helicenes (7-TH, Figure 1), which are configurationally stable heterohelicenes, potentially very interesting for applications in optoelectronics,3 catalysis,4 and biology.5 In particular, transition metal-based 7-TH systems are an extremely appealing class of complexes, in which the coordination of metals with the \u3c0-helical ligand, bearing proper coordinating groups, provides unusual chiral architectures. Indeed, the selective functionalization of 2 and 13 positions of the 7-TH scaffold allows the introduction of a variety of substituents, including those with efficient coordinating ability (e.g. cyano, phosphane, phosphine oxide). In this communication we report our recent studies on the synthesis and characterization of 7-TH-based organometallic complexes, and their potential applications in optoelectronics and catalysis

Multicolour fluorescent "sulfide-sulfone" diarylethenes with high photo-fatigue resistance.

Compact "push-pull" photochromic diaryethenes (DAEs) with unsymmetric oxidation pattern of the benzothiophene core display multicolour fluorescence switching, as a result of dual emission from both "open" and "closed" forms. These DAEs also present an unprecedented photo-fatigue resistance