Optical imaging of anatomical maps derived from magnetic resonanceimages using time-independent optical sources

Presents a model suitable for computing images of absorption cross sections of thick tissue structures illuminated at near infrared (NIR) wavelengths from tomographic projection data. Image reconstruction is accomplished by solving a system of linear equations derived from transport theory. Reconstruction results using different algebraic solvers are shown for anatomical maps of the breast, derived from magnetic resonance imaging data, containing two simulated pathologies, in which case qualitatively good reconstructions were obtained. Evaluation of magnetic resonance (MR) data to optimize NIR optical tomographic imaging methods and to assess the feasibility of a combined MR-optical measurement scheme is discussed     

Pain threshold in man

The design and application of an apparatus for measuring pain threshold by controlling the conditions of an experiment carefully and measuring stimulus and response parameters precisely are described. Heat generated by an incandescent source, focused on a small area of the subject's forehead, was used as the stimulus to determine the cutaneous pain threshold. The equipment was in different experiments in which the threshold of thermocutaneous pain was evaluated with and without the use of an analgesic. The analgesic Pirazolane was found to reduce thermocutaneous pain threshold and to diminish the average duration of alpha rhythm blockade and the response of galvanic skin resistance. The results of these experiments with constituents of marijuana indicated that canabidiol provokes and increases the sensibility of pain reactions while both Δ9 THC and canabinol do not modify the pain threshold     

Comparing the motivations of Spanish and Finnish computer personnel with those of the United States

A survey of perceptions of IS personnel – managers, technical specialists and programmer/analysts – was conducted by the Association for Technical Information in Spain, using the JDS/DP, a modification of the job diagnostic survey instrument. Data were collected on fifteen job variables, related to four motivation aspects: job components, satisfaction levels, need for growth/achievement and goal participation/feedback. The results were compared with those of a similar survey for the same job types in Finland. Results were also compared with the norms developed for computer personnel in the USA. The survey revealed that personnel attracted to the computer field have a high need for growth and a low need for social interaction. It also revealed that the work itself was ranked highest among eleven motivating factors. For both Spain and Finland, the technical specialist job had a mis-match between the job's motivating potential and the employee's need for growth, compared with similar personnel in the USA. By examining the core job dimensions, managers can redesign the job to produce a match between these two major components of motivation.     

Interferon-gamma activates the oxidative killing of Candida albicans by human granulocytes

The sequence proline-proline-glycine-proline is highly conserved in cytochrome P450 families 1 and 2, and similar proline rich sequences are found in other cytochromes P450. Since this sequence immediately follows the NH2-terminal hydrophobic membrane insertion signal, it potentially could function as a signal either for retention of cytochrome P450 in the endoplasmic reticulum or for its correct orientation in the membrane. To test this possibility, DNA sequence coding for this tetrapeptide was deleted from cytochrome P450 2C2 cDNA. Translation of the mutated mRNA in a reticulocyte cell-free system containing canine microsomal membranes resulted in the insertion of the protein into the membrane with a topology indistinguishable from that of normal cytochrome P450 2C2. The mutated protein was expressed in COS1 cells and its distribution, assayed by immunofluorescence, was similar to that of cytochrome P450 2C2. Furthermore, if a short peptide containing a potential glycosylation site was fused to the N-terminus of the mutant protein, the new hybrid protein was glycosylated in COS1 cells and the carbohydrate moiety remained sensitive to cleavage by endoglycosidase H. These results indicate that the protein was inserted and retained in the endoplasmic reticulum membrane. Pulse-chase studies showed that the mutated protein was degraded about four times as fast as cytochrome P450 2C2. In contrast to cytochrome P450 2C2, no (omega-1) hydroxylase activity was detected in COS1 cells expressing the mutated protein at similar steady-state levels as the wild-type protein. These results indicate that, although the conserved PPGP tetrapeptide is not required for cellular localization of cytochrome P450 in the endoplasmic reticulum membrane, its deletion decreases the stability of the protein and abolishes enzymatic activity.     

Ankle performance after ankle fracture: a randomized study of early mobilization

Low concentrations of some neutral dipeptides, such as L-Ala-L-Ala, rapidly disrupt rat liver lysosomes. The phenomenon has been attributed to an osmotic imbalance generated by the production of amino acids in the lysosome by lysosomal dipeptidase activity. This hypothesis is challenged by testing several pairs of dipeptides available in both D- and L-forms and a range of dipeptides whose susceptibility to lysosomal dipeptidase activity is known. A good correlation was found between the lytic ability of dipeptides and their capacity to cross the lysosome membrane and be hydrolysed by lysosomal dipeptidase. The osmotic-imbalance hypothesis is critically evaluated in the light of the results and of recent information concerning the carrier-mediated transport of amino acids and dipeptides across the lysosome membrane. It is concluded that intralysosomal generation of amino acids remains the most plausible explanation of the lytic activity of dipeptides, and that the dipeptide porter(s) in the lysosome membrane must have higher Km than the amino acid porters.     

Study of 18-cm long single-sided AC-coupled silicon microstripdetectors

The SSC GEM silicon Central Tracker design incorporated 18-cm long single-sided AC-coupled silicon microstrip ladders. Compared to the 12-cm long ladders considered in the preliminary stages of the tracker design, the 18-cm long ladders have the advantage of reduced cost, channel count and overall power consumption, and led to a simplified tracker assembly. However, such long ships also present the challenge of maintaining satisfactory performance. The increased capacitance and series resistance contribute to lower signal-to-noise ratios, longer time walk, higher power consumption per channel and increased probability of crosstalk to neighboring channels. In this paper, an accurate method to calculate the geometric capacitance of the AC-coupled microstrips is presented and the calculated results are compared with measurements, SPICE simulations are performed to predict the noise, the extent of interstrip capacitive coupling and the dispersion of the detector signal due to the finite series resistance of the metal strips and the long length of the detector. The influence of the preamplifier current and the shaping time on the signal and noise levels is also presented. The study concludes that the 18-cm long ladders can successfully satisfy the performance goals of the GEM silicon Central Tracker     

Exchange and oxidation of CO on O-predosed Rh---Al2O3 and Rh---CeO2 catalysts

Exchange and oxidation of C¹⁶O were investigated at 450°C on ¹⁸O-predosed Rh and Pt catalysts supported on A1₂O₃, CeO₂ and CeO₂-Al₂O₃. In all cases, a rapid exchange of C¹⁶O with the surface can be observed. CO oxidation leads to C¹⁶O₂, C¹⁶O¹⁸O and C¹⁸O₂. Significant formation of C¹⁶O₂ is due to the relatively high ¹⁶O coverage in reaction resulting from the C¹⁶O exchange and from an exchange between O surface species and ¹⁶O internal atoms. Hydrogen is also formed via a water-gas shift reaction (CO + surface OH) in higher proportion on CeO₂-containing catalysts than on A1₂O₃. Chlorine inhibits all the reactions (exchange, oxidation and WGS) and particularly the internal exchange.