Immobilization/stabilization of lipase fromCandida rugosa

With the aim of fixing the enzyme to the matrix by multiple covalent linkages, lipase from Candida rugosa (formerly cylindracea) has been insolubilized through its amino groups on Sepharose 6B previously activated with 2,3-epoxy-1-propanol. Two main variables that are known to control the number of bonds formed have been tested: the contact time between enzyme and activated support, and the temperature at which the immobilization reaction is carried out. Studies on activity and stability of the different derivatives prepared showed that higher temperatures and longer contact times lead to insolubilized enzymes that are more resistant to inactivation by temperature and the presence of organic solvents. At 50 degrees C and pH 7.2, the insoluble lipase was found to be 140 times more stable than its soluble counterpart.     

Solving problems of project management with a self enforcing network (SEN)

The usage of AI techniques when dealing with problems of management always implies the task to understand the respective problem in terms of these techniques, in this case in terms of a specific neural network. That is, by the way, at its core a hermeneutical problem, namely of ??understanding?? the problem situation in the sense of hermeneutics. I shall demonstrate how a specific self-organized learning network that we have newly developed can be applied to problems of project management. This new network SEN will be described and its possibilities are shown by the application to different problems of project management, e.g. the selection of suited collaborators for a specific project, the classification of problematic customers or also the selection of suited procedures for project management in a specific firm. The SEN seems to be a universal instrument for different purposes as many reactions from managers in several large firms have shown. In particular SEN seems to be more suited for practical problems than some standard software we compared with SEN.     

Development of small molecules that mimic the binding of ω-conotoxins at the N-type voltage-gated calcium channel

Cone snails (Conidae) are marine predators with some extraordinary features. Their venom contains a hundred or more peptides that target numerous ion channels and receptors in mammals, including several that are involved in disease. omega-Conotoxins from fish hunting snails are 24-27 residue peptides with a rigid 4-loop cysteine framework that target the N-type voltage-gated calcium channel (VGCC). Two omega-conotoxins, MVIIA and CVID are currently in clinical development for chronic pain management (Ziconotide or Prialt, and AM336, respectively). In an attempt to develop small molecule equivalents of CVID, we defined the Calpha-Cbeta vectors of the residues believed to be important for binding to the N-type VGCC. Using these vectors, we undertook a virtual screening of virtual libraries approach to identify compounds that matched the pharmacophore. Cyclic pentapeptides containing residues of loop 2 of CVID, with one or more being a D-amino acid were designed and synthesised and were found to be active at the N-type VGCC (IC50 approximately 20 microM). Agreeing with the specificity profile of CVID, molecules were inactive at the P/Q-type VGCC.     

Control of a multisubunit DNA motor by a thermoresponsive polymer switch

The conjugation of thermoresponsive polymers to multisubunit, multifunctional hybrid type 1 DNA restriction-modification (R-M) enzymes enables temperature-controlled "switching" of DNA methylation by the conjugate. Polymers attached to the enzyme at a subunit distal to the methylation subunit allow retention of DNA recognition and ATPase activity while controlling methylation of plasmid DNA. This regulation of enzyme activity arises from the coil-globule phase transitions of the polymer as shown in light scattering and gel retardation assays.     

Universal covers for Hausdorff limits of noncompact spaces

We prove that if is the Gromov-Hausdorff limit of a sequence of complete manifolds, , with a uniform lower bound on Ricci curvature, then has a universal cover.

     

Non-equilibrium cooling of Poncirus trifoliata (L.) embryonic axes at various water contents

The present study investigated the rate of temperature change within axes of Poncirus trifoliata during cooling and warming by various methods. Cooling rates ranged between 0.17 and 170 degree (C per second, and warming rates of 1.25 and 600 degree C per second were measured when axes were warmed at room temperature or in water at 40 degree C, respectively. Partial drying increased the cooling rate within axes in direct contact with the cryogen, but did not affect the cooling or warming rates within axes enclosed in a double layer of lightweight aluminium foil. The procedures described illustrate the orders of magnitude that separate extremes of the range of cooling or warming rates attained using methods commonly employed in cryopreservation studies. Quantifying these rates allows the relationship between cooling rate, water content and survival of hydrated embryonic axes to be explored.     

Identification of non-idealities in gel electrophoresis

The molecular weight separation, which is the second dimension of two-dimensional gel electrophoresis, is studied quantitatively with the goal of improving positional predictability and reproducibility. Mathematical modeling of carrier electrolyte dynamics is used to track the progress of a stacking front as a function of coulombs passed. In all test cases, the front moves more slowly than predicted and shows both curvature and tilt. These systematic deviations from the model are found to be influenced by a variety of factors, including both design and operating features. These factors are largely explained, and suggestions are made for improvements.     

Self-assembled and self-sorted array of chemically active beads for analytical and biochemical screening

A technique for generating a general screening platform consisting of dots of immobilized beads on silicon has been developed via self-sorting and -assembly of different kinds of beads. The dots are defined by a teflon-like film, which due to its hydrophobic characteristics also prevents cross-contamination of liquid from different dots. To enable functionalization of individual dots with different target molecules simultaneously a new way of microcontact printing has been explored where different target solutions are printed in parallel using one stamp. In order to show that this platform can be designed for both biochemical assays and organic chemistry, streptavidin-, amino- and hydroxy-functionalized beads have been self-sorted and -assembled both on separate and common platforms. The self-sorting and -arrangement are based on surface chemistry only, which has not previously been reported. Beads of different sizes and material have successfully been immobilized in line patterns as narrow as 5 mum. Besides silicon, quartz and polyethylene have also been used as substrates.     

Ensemble and Single Particle Laser probe sizing results for gas atomized zinc powders

On-line characterization of powder and droplets during gas atomization of molten metals and alloys offers extensive opportunities for real-time process monitoring and control. The capability to make on-line measurements can significantly reduce tedious and costly powder classification, which, currently, is always carried out subsequent to the atomization process. Two laser-based particle sizing instruments, the EPCS (ensemble instrument) and PCSV (single particle instrument), were used during gas atomization of zinc with a double Coanda nozzle configuration. The laser instruments were positioned in the duct leading from the bottom of the atomization tower to the powder collection cyclone. The effect of gas to metal ratio on particle size was studied by varying the atomization gas pressure from 0.69 MPa to 1.03 MPa. Air was used as the atomizing gas for some of the 0.69 MPa runs, while nitrogen was used for all of the higher-pressure runs. Experimental apparatus and procedures for atomization and on-line powder sizing with the EPCS and PCSV are described. EPCS and PCSV measurements, which were compared with standard sieve analyses, indicate that the ensemble instrument is a good candidate for on-line process monitoring and control.