Properties of titanium-containing sol-gel films modified with copper and vanadium oxides

Translated from Steklo i Keramika, No. 1, pp. 4–6, January, 1994.     

Worm plots

Scientists sometimes spend hours conducting experiments only to find that the resulting data proves difficult to analyze with traditional visualization techniques. A typical laboratory experiment, for example, will setup several systems in each of two or more groups-a control group and various treatment groups. The investigator will then measure various parameters for each system over time (sometimes dozens to hundreds of parameters). The investigator tries to answer this question: What is different between the control and treatment groups? Field monitoring of polluted and unpolluted sites within a region result in the same kinds of data and the same difficulties in visualization. Plotting multiple lines on a single 2D plot quickly gets confusing. Plus, the dynamic interactions between parameters can be hard to see. 3D visualizations help researchers make qualitative insights about data more easily. We developed a 3D plotting technique, called “worm plots”, for visualizing these kinds of data. Our visualization tool examines how groups of points change over time. If we plot circles for each time slice, then these circles will change their relative sizes and positions as time goes by. To visualize these evolving dynamics, we connect these time slices with conic sections. This gives us spacetime worms that can be displayed graphically. In our experience, these simple circular cross sections work best when exploring data. They can be rendered quickly and give an easily intuited summary of each group. Further enhancements tend to make the image busy and difficult to interpret     

Singular value properties of LQ regulators

The closed-loop singular values of an LQ regulator transfer function are proved to be no greater than the singular values of the open-loop transfer function and, in the case of output-weighted cost function, to be no greater than the output-weighting parameter     

Nanotomography: Ellipsometric Spectral Tomography of Surface Nanostructures Metal–Oxide

General methodological and mathematical aspects of using tomographic approach to reconstructing the inner structure of surface layers and films on the most abundant nonuniformity types characteristic of heterogeneous physico-chemical nanosystems are discussed. Spectral ellipsometric measurement of light reflected from a nonuniform surface nanolayer allows substantiating spectral-tomographic principle and reconstructing the inner structure of the layer by solving an integral equation of the 1st kind. Principles and mathematic fundamentals of ellipsometric spectral tomography are presented, which may be used in nondestructively monitoring the distribution of physico-chemical properties over the bulk of nonuniform metal–oxide surface structures.     

The effects of induction conditions on production of a soluble antitumor sFv in Escherichia coli

CC49 is a second generation monoclonal antibody(mAb) with highaffinity to a pancarcinoma antigen, TAG-72. A single-chain Fv(sFv)ofCC49 may have a role in managing human carcinomas. Most reportedsFvs have been expressed as insoluble products that must besolubilized and renatured. Soluble sFv expression is advantageousas activity can be assayed directly from the periplasmic fraction.Also, gene-level immunoconjugates may not be amenable to refoldingprotocols. Using a vector that carries the tac promoter andomp A signal, we have examined the effects of four variableson the expression and accumulation of soluble CC49 sFv: (i)linker sequence joining VL and VH, (ii) isopropylthio-ß-D-galactosideconcentration for induction, (iii) temprature, and (iv) theaddition of nonmetabolizable sugars to the medium. We have beenable to demonstrate, using rapidly prepared periplasmic extracts,that the yield of soluble sFv improves by the addition of 0.4Msucrose to the medium and by inducing expression with a verylow concentration of IPTG (0.02–0.03 mM). Under theseinduction conditions periplasmic extracts demonstrate increasedexpression of the sFv, as shown by the larger amount of a 27kDa band on SDS-polyacrylamide gel, and an increased abilityto inhibit binding of the mAb CC49 to immobilized tumor extracts.     

IEA joint trials: New lessons from old plantations

Two international trials of potential biomass species families and clones planted in 1985 have been analyzed to determine changing patterns in growth, diseases, and insects. In the Swedish trial, with close spacing and short rotations, Salix viminalis clones gave the best average yield of 17.4 Mg/Ha/yr on the first coppice rotation. In the Minnesota, USA trial, with wider spacings and a longer rotation Populus alba hybrid clones gave the best average yields of 5.5 Mg/Ha/yr. The most important disease and insect problems encountered were Septoria musiva stem cankers on some Populus clones; frost die back in some Salix clones; and the leaf blotch miner, Fenusa dohrnii, on most Alnus families. Recommendations for future international cooperation in field trials are presented.     

Kinetic behaviour of muscle LDH immobilized in nylon tubing

Immobilization was carried out of the lactate dehydrogenase (LDH) from rabbit muscle (EC 1.1.1.27), cross-linked through the bifunctional reactive glutar-aldehyde on to nylon tubing (1 m long, 53cm² internal surface area). Immobilized LDH inactivation kinetics are of first order (t_1/2 = 3·6 years, k = 5·4,e^?4 day^?1 to 5°C). The smaller effect of pH on activity than in the case of LDH in solution can be explained on the basis of limitation to proton diffusion towards the support. A limiting effect to free external diffusion of the substrate towards and products from the support was also observed, an effect which seems to determine the effective kinetic behaviour of immobilized LDH. The apparent optimum temperature is centred around 40°C, observing a clear inactivation (thermal denaturation) above this temperature. In the temperature range studied (10–40°C), the co-existence was seen of a kinetic control accompanied by another control, involving diffusional transport of substrates and products, on the global activity of the immobilized enzyme. This makes the Arrhenius profiles curvilinear. Both graphic and statistical non-linear regression analysis of the kinetic data—rate, v, versus substrate concentration [S]—carried out under conditions in which the diffusional limitations can be considered negligible (high recirculation flow rate), permitted investigation of the intrinsic kinetic behaviour of immobilized LDH. In this sense, it can be deduced that the rate equation to which these data seem to be fitted is of the polynomial quotient type in [S] of minimum degree 2:2. Although the diffusional limitations have a marked effect on the type of global kinetics shown by immobilized LDH, temperature was not found to affect its v[S] behaviour. The experimental evidence obtained thus indicates that the rate equation in the 10-40°C temperature range continues to be a rational equation of at least degree 2:2 in [S].