Significance of local extradural cooling on cervical spinal cord (experimental study)

The PQ-interval was measured while resting supine before exercise testing, in the erect position on the bicycle before starting exercise, and resting supine after exercise in 68 men 6--8 weeks after acute myocardial infarction. During a 6-year follow-up period the death was non-sudden (greater than 1 hour) in 25 of these patients. In this group the PQ-time was significantly shorter (p less than 0.001) during somatomotor activation on the bicycle before exercise than resting supine. The same directional change (p less than 0.01) was seen in the sudden death (less than 1 hour) group (N = 21), but not in the patients who survived. PQ-time at supine rest before exercise testing, however, was significantly shorter (p less than 0.02) in surviving patients than in the non-sudden death group. The possible mechanisms of these, and of previously reported changes in the R-wave amplitudes and QT-times, are discussed.     

Measuring client satisfaction with public education I: meeting competing demands in establishing state-wide benchmarks

By its very nature, a large-scale evaluation of client satisfaction with public education using a quantitative approach, places almost impossibly competing demands on the research methodology. This paper reports on the use of a suite of Rasch measurement techniques to meet the competing demands in establishing state-wide benchmarks relating to the School Opinion Survey carried out over 1200 government schools in one state of Australia. Although the evaluation had to establish system-wide representative parent and student benchmarks, meaningful quantitative estimates of client satisfaction had to be provided at the smallest public schools. The final 20-item School Opinion Survey Parent and Student Forms were designed following feedback from the administration of trial forms. Instrument development was monitored by the results of Rasch modeling. The Rasch modeling property of specific objectivity was empirically verified when calculation of identical benchmark estimates resulted from the construction of simulated population proportional samples using sample:population size weightings.     

A method of creating new valency entries

Information on subcategorization and selectional restrictions in a valency dictionary is important for natural language processing tasks such as monolingual parsing, accurate rule-based machine translation and automatic summarization. In this paper we present an efficient method of assigning valency information and selectional restrictions to entries in a bilingual dictionary, based on information in an existing valency dictionary. The method is based on two assumptions: words with similar meaning have similar subcategorization frames and selectional restrictions; and words with the same translations have similar meanings. Based on these assumptions, new valency entries are constructed for words in a plain bilingual dictionary, using entries with similar source-language meaning and the same target-language translations. We evaluate the effects of various measures of semantic similarity.     

Virus Matryoshka: A Bacteriophage Particle—Guided Molecular Assembly Approach to a Monodisperse Model of the Immature Human Immunodeficiency Virus

Immature human immunodeficiency virus type 1 (HIV‐1) is approximately spherical, but is constructed from a hexagonal lattice of the Gag protein. As a hexagonal lattice is necessarily flat, the local symmetry cannot be maintained throughout the structure. This geometrical frustration presumably results in bending stress. In natural particles, the stress is relieved by incorporation of packing defects, but the magnitude of this stress and its significance for the particles is not known. In order to control this stress, we have now assembled the Gag protein on a quasi‐spherical template derived from bacteriophage P22. This template is monodisperse in size and electron‐transparent, enabling the use of cryo‐electron microscopy in structural studies. These templated assemblies are far less polydisperse than any previously described virus‐like particles (and, while constructed according to the same lattice as natural particles, contain almost no packing defects). This system gives us the ability to study the relationship between packing defects, curvature and elastic energy, and thermodynamic stability. As Gag is bound to the P22 template by single‐stranded DNA, treatment of the particles with DNase enabled us to determine the intrinsic radius of curvature of a Gag lattice, unconstrained by DNA or a template. We found that this intrinsic radius is far larger than that of a virion or P22‐templated particle. We conclude that Gag is under elastic strain in a particle; this has important implications for the kinetics of shell growth, the stability of the shell, and the type of defects it will assume as it grows.     

A channel flow cell system specifically designed to test the efficiency of redox shuttles in dye sensitized solar cells

The construction and use of a thin layer flow cell test system employing a TiO₂ working electrode, a platinum quasi-reference electrode and the ruthenium dye (H₂-dcbpy)Ru(NCS)₂ (H₂-dcbpy=2,2′-bipyridine-4,4′-dicarboxylic acid) is described. The efficient design enables significant advantages to be gained over presently available procedures for the measurement of photocurrents of dye-sensitized solar cells. The widely used iodide/triiodide redox shuttle system has been investigated over a wide range of conditions. A linear dependence of photocurrent on cation radius was revealed. Under certain conditions, the photocurrent measured in the presence of the Li⁺ cation is five times larger than when the (C₄H₉)₄N⁺ cation is used. Additionally, the addition of low concentrations of cations with small diameters has a significant catalytic enhancement effect on the photocurrent. Other redox shuttles, based on ferrocene, thiocyanate, triiodide and bromide, were tested for their performance in the flow cell and compared to iodide. However, despite some apparent thermodynamic advantages, the photocurrents obtained with these redox shuttles were more than two orders of magnitude lower than those measured with iodide. This finding implies that the efficiency of redox shuttles is limited by kinetic restraints rather than their thermodynamic properties and confirms that the iodide/triiodide system is the dominant redox shuttle.     

Big Brother Has Been Here All Along.

As a management consultant with a company who create products for E-businesses in the field of secure data exchange, I am constantly asked for my views on the RIP Bill. As most of you will know, RIP stands for ‘Regulation of Investigatory Powers’, and the Bill is designed to allow MI5 to monitor information exchanged over the Internet.     

Kinetic and mechanistic evaluation of tetrahydroborate ion electro-oxidation at polycrystalline gold

The anodic oxidation of tetrahydroborate ion is studied in NaOH at stationary and rotating polycrystalline Au disk electrodes. Linear sweep and cyclic voltammetry are applied varying the scan and rotation rate from 0.005 to 51.200 V s⁻¹ and from 52.3 to 314.1 rad s⁻¹, correspondingly. The effects of variation of BH₄⁻ and NaOH concentrations as well as of the potential limits of the ranges studied have been initially followed. Most of the experiments have been carried out with 10.9 mM NaBH₄ in 1.04 M NaOH at 293 K in the potential range from −1.300 to 0.900 V (vs. Ag/AgCl). It is found that 6 electrons are exchanged in the overall oxidation transformation. The kinetic analysis of the processes determining the two anodic peaks recorded under static conditions at scan rates lower than 0.500 V s⁻¹ shows that 1.4 electrons are exchanged in the potential range of the first one (at ca −0.5 V), while the rate of the second one (at ca +0.3 V) is determined by a quasi-reversible 1-electron transfer reaction. A kinetic evidence for the participation of surface bound intermediates in the electro-oxidation process is provided. Two additional well outlined anodic peaks are recorded in the aforementioned potential range under specific experimental conditions. A quasi-8 electron mechanism involving four oxidation and hydrolysis steps is advanced to explain the experimental results. It accounts for the involvement of borohydride oxidation species and the Au⁺/Au³⁺ mediator couple.