On point-based temporal disjointness

We address the problems of determining consistency and of finding a solution for sets of three-point relations expressing exclusion of a point from an interval, and for sets of four-point relations expressing interval disjointness. Availability of these relations is an important requirement for dealing with the sorts of temporal constraints encountered in many AI applications such as plan reasoning. We prove that consistency testing is NP-complete and finding a solution is NP-hard.     

Mechanism of densification and crystal perfection of poly(ethylene terephthalate)

Amorphous poly(ethylene terephthalate) has been isothermally annealed in a wide range of temperatures from T_g to T_m. The effects of temperature and time of thermal treatment on density, melting curve and WAXS have been systematically explored. The results showed that densification and crystal perfection take place through a step mechanism involving partial melting and diffusion. The evaluation of the activation energies suggests that diffusion is the rate determining step in the low temperature range.     

Temporal and spatial repetition blindness: Effects of presentation mode and repetition lag on the perception of repeated items.

In this study, participants were asked to identify briefly presented 5-letter (Experiments 1-3) or 2-letter (Experiment 4) strings. Identical items in a repeated trial were identified worse than their counterparts in a nonrepeated trial, indicating repetition blindness (RB; N. G. Kanwisher, 1987). In Experiment 1, RB occurred regardless of whether items were presented successively or simultaneously. In Experiments 2-4, RB occurred regardless of whether 2 simultaneously presented items were spatially close or far apart. The magnitude of RB, however, varied with presentation mode and repetition lag: RB was smaller in simultaneous than successive presentation, and RB increased and then decreased with the number of items separating 2 identical ones. These results provide important constraints in the interpretation of RB. A model that attributes RB to the refractoriness of perceptual recognition units is proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Input-output stability of systems with backlash

The objective of this work is to study the stability of systems with backlash, from an input-output point of view. In the first part, an L_∞ analysis is addressed. This analysis provides not only conditions for boundedness of the loop signals, but also results on existence of solutions, based on Schauder fixed point theorem. In the second part, the system is studied using an L₂ or conic sector approach. The backlash graph is confined into certain conic sector, which is shown to be optimum or maximal. The conic inequality induces frequencial conditions on the linear part, which are further relaxed introducing dynamic multipliers. In the third part, both L_∞ and L₂ techniques are combined reaching a final criterion which results in a Popov-like stability condition.     

Neurophysiological assessment of children with obstetric brachial plexus palsy]

INTRODUCTION: The objectives of the neurophysiological evaluation of infants with brachial plexus palsy are to determine the time of occurrence of the lesion, to locate the lesion and to determine its course. METHODS AND CONCLUSIONS: These objectives are achieved by studying affected upper extremity muscles by needle electromiography (EMG) and affected nerves by motor and sensory conduction studies. EMG is performed in the first week of life in those patients with brachial plexus palsy of unknown etiology to determine the age of the lesion for medico-legal reasons. EMG is performed before surgery for tendon transfer in the selected muscles to assure that they are normal. EMG and motor and sensory conduction studies are performed at the age of 3 and 6 months in infants with less than 4 muscle weakness to determine candidates for surgical exploration. Motor and sensory nerve conduction studies are performed intraoperative to determine the functional status of the affected axons and the best surgical procedure (neurotization, neurolysis and/or neuroma resection and homologous nerve graft).     

Flame temperature and location measurements of sooting premixed Bunsen flames by rainbow schlieren deflectometry

Rainbow schlieren deflectometry (RSD) provides a simple and nonintrusive way of determining the temperature field of axisymmetric flames. This technique is specially suited for the detection of large temperature gradients, such as those near the flame location. We explore the feasibility and accuracy of using RSD to obtain the flame location and thermal structure of premixed Bunsen flames for varying fuel types, equivalence ratios, and soot loadings. Uncertainty analysis is also carried out to provide various ways to reduce RSD experimental error. The RSD technique is demonstrated to give useful data even for moderately and heavily sooting flames.     

Crystallisation kinetics and morphology of high density polyethylene containing organic and inorganic pigments

Some organic pigments, present in very small amounts (0.1 to 0.2%), can cause warpage and shrinkage phenomena in moulded parts of linear polyethylene. Investigations on such phenomena have been carried out by dilatometric and morphological analysis. The influence on polyethylene crystallisation kinetics and morphology of such organic and inorganic pigments, which do not cause any deformation effect, has been studied. The experimental results show that only organic pigments increase the crystallisation rate, by acting as nucleating agents; in these cases, moreover, the crystalline grain is smaller and the typical morphology of polyethylene crystallised in bulk is altered. A possible correlation between the nucleating action and the warpage effect of organic pigments on moulded polyethylene is discussed.     

Bowman-Birk inhibitors in lentil: Heterologous expression,functional characterisation and anti-proliferative properties in human colon cancer cells

A full-length cDNA, encoding a Bowman-Birk protease inhibitor (BBI), was isolated from lentil immature seeds. The deduced amino acid sequence was longer than that of the BBI extracted from lentil seeds and contained two binding sites; the first inhibitory site inhibits trypsin whereas the second one inhibits chymotrypsin. In order to characterize this lentil BBI, a longer (complete) and its C-terminally processed (mature) form were heterologously expressed in the yeast Pichia pastoris. The recombinant BBI proteins proved to be active against trypsin and chymotrypsin, showing K_i values at nanomolar levels. Mass spectrometry analysis revealed that complete BBI was composed of an array of molecular masses, whereas mature BBI showed the presence of a major peak of the expected size. The effects of mature BBI on the growth of human colon adenocarcinoma HT29 and colonic fibroblast CCD-18Co cells were evaluated. Lentil BBI was able to inhibit the growth of such cells at concentrations higher than 19 μM, in a concentration-dependent manner; by contrast, the CCD18-Co cells were unaffected. These data broaden our knowledge of the beneficial biological activities of naturally-occurring BBI proteins and address the need for systematic evaluation of natural variants in order to design novel strategies in preventive medicine.     

New hydroxyproline based methacrylic polybetaines: Synthesis, pH sensitivity and catalytic activity

The synthesis of two new types of methacrylic polybetaines bearing trans-4-hydroxy-l-proline connected via its hydroxyl group is described, one with an aliphatic spacer of 6 carbon atoms and the other without any spacer. The pH sensitivity in aqueous media and the catalytic activity of the products in asymmetric aldol additions have been studied. The two polyzwitterions show an isoelectric point (IEP) close to 3. Swelling of networks prepared with the two monomers exhibit reversible pH sensitivity; the largest the pH distance from the IEP, the higher the net charge (positive or negative) and the higher the swelling. At basic pH and an ionic strength of 0.15, maximum swelling degrees of around 11 and 24 (g water/g polymer) have been found for the systems with and without spacer respectively. The polymers have been shown to be efficient catalysts for aldol reactions under homogeneous conditions in DMF but not in water.     

Activated α,β‐Unsaturated Aldehydes as Substrate of Dihydroxyacetone Phosphate (DHAP)‐Dependent Aldolases in the Context of a Multienzyme System

The utility for carbon‐carbon bond formation of a multienzyme system composed of recombinant dihydroxyacetone kinase (DHAK) from Citrobacter freundii, the fructose bisphosphate aldolase from rabbit muscle (RAMA) and acetate kinase (AK) for adenosine triphosphate (ATP) regeneration has been studied. Several aldehydes with great structural diversity, including three α,β‐unsaturated aldehydes, have been analysed as acceptor substrates. It was found that α,β‐unsaturated aldehydes bearing an electron‐withdrawing group in the β position to the double bond with a trans configuration are good acceptors for RAMA in this multienzyme system. The aldol reaction proceeds with excellent D ‐threo enantioselectivity and the aldol adduct is obtained in good overall yield. The L ‐threo and D ‐erythro enantiomers are also accessible from rhamnulose 1‐phosphate aldolase (Rha‐1PA) and fuculose 1‐phosphate aldolase (Fuc‐1PA) catalysed reactions, respectively.