Thinkorama

Thinkorama is a special section devised for this issue dedicated to ideas, thinking about ideas, writing about and making ideas. Full credit for the title must go to champion and first lady of architectural ideas, director of the Canadian Centre for Architecture, Phyllis Lambert, who coined the phrase on the eve of a presentation of Cedric Price's ‘Potteries Thinkbelt’ in November 2003 at the University of Westminster. The event, called ‘SuperCrit’, was endorsed by Price, but his untimely death in the summer of that year prevented him from presenting the project himself. It was therefore handed to a group of friends and associates to argue the profundity of this great architectural work-on-paper. As for now … Price would have us remember, it is up to all to keep on thinking. Copyright © 2005 John Wiley & Sons, Ltd.     

Glycoalkaloid content of potatoes sold in Czechia

Glycoalkaloid levels in different cultivars collected from three regions were monitored during two years. With the exception of Karin, one of the most widely grown cultivar in the Czech Republic, none of the cultivars used for human consumption exceeded the levels considered safe. The average of total glycoalkaloids content for tested cultivars ranged from 31 to 166 mg/kg fresh weight. There were no significant differences between glycoalkaloid levels in tubers from different regions. Attention was paid to the adequate sampling procedure.     

Predicting capacities required in cardiology units for heart failure patients via simulation

The management of a department of cardiology has to plan the capacity of both elective and non-elective patients. Heart failure (HF) patients are admitted to the hospital in a non-elective way. The precision with which the capacity needed for non-elective patients can be predicted determines the degree of flexibility in planning the admission of elective patients. In this study we want to determine how accurately we can predict the bed occupancy of HF patients using a simulation model. Data of the year 2000 were used to obtain the necessary probability distribution functions. Data from the year 2001 were used for determining the prediction accuracy. The results show that the arrival of new HF patients can be adequately predicted. However, the bed occupancy by new and especially current patients is predicted less accurately. Still in 70% (90%) of the days of a 5-day-prediction interval the error is at most one (two) bed(s). The results may improve if the cardiologist is asked to predict the length of stay of the current patients.     

An enzyme module system for the synthesis of dTDP-activated deoxysugars from dTMP and sucrose

A flexible enzyme module system is presented that allows preparative access to important dTDP-activated deoxyhexoses from dTMP and sucrose. The strategic combination of the recombinant enzymes dTMP-kinase and sucrose synthase (SuSy), and the enzymes RmlB (4,6-dehydratase), RmlC (3,5-epimerase) and RmlD (4-ketoreductase) from the biosynthetic pathway of dTDP-beta-L-rhamnose was optimized. The SuSy module (dTMP-kinase, SuSy, +/-RmlB) yielded the precursor dTDP-alpha-D-glucose (2) or the biosynthetic intermediate dTDP-6-deoxy-4-keto-alpha-D-glucose (3) on a 0.2-0.6 g scale with overall yields of 62 % and 72 %, respectively. A two-step strategy in which the SuSy module was followed by the deoxysugar module (RmlC and RmlD) resulted in the synthesis of dTDP-beta-L-rhamnose (4; 24.1 micromol, overall yield: 35.9 %). Substitution of RmlC by DnmU from the dTDP-beta-L-daunosamine pathway of Streptomyces peucetius in this module demonstrated that DnmU acts in vitro as a 3,5-epimerase with 3 as substrate to yield 4 (32.2 mumol, overall yield: 44.7 %). Chemical reduction of 3 with NaBH4 gave a mixture of the C-4 epimers dTDP-alpha-D-quinovose (6) and dTDP-alpha-D-fucose (7) in a ratio of 2:1. In summary, the modular character of the presented enzyme system provides valuable compounds for the biochemical characterization of deoxysugar pathways playing a major role in microbial producers of antibiotic and antitumour agents.     

Cadmium and zinc response of the fungi Heliscus lugdunensis and Verticillium cf. alboatrum isolated from highly polluted water

The aquatic hyphomycete Heliscus lugdunensis and the terrestrial fungus Verticillium cf. alboatrum, both isolated from a highly polluted surface water, were investigated for their tolerance against Cd and Zn. Hl-H4 showed a 50% growth inhibition at 0.1 mM Cd, whereas at 0.7 mM Cd the growth of Va-H4 was only reduced by 30%. The fungi also showed a remarkable difference in their Zn-tolerance. The growth of Va-H4 was not inhibited at 1 mM Zn, whereas for Hl-H4 no growth occurred above 0.3 mM Zn. The biosorption and accumulation capacities for Cd or Zn of both fungi differed between the fungal species. In a 0.1 mM Cd-medium Hl-H4 biosorbed 15-fold and accumulated 39-fold more Cd than Va-H4. Exposure to 0.3 mM Zn resulted in a 13-fold higher biosorption and 11-fold higher accumulation for Hl-H4 than Va-H4. As glutathione (GSH) is known to be involved in the phytochelatin synthesis and other stress related processes we investigated its synthesis. Both fungi increased their synthesis of GSH in response to Cd. For Hl-H4 a concentration of 0.0125 mM Cd, corresponding to an intracellular Cd content of 2.1 nmol Cd mg(-1) dw, increased the GSH content, whereas Va-H4 only responded with a higher production of GSH at 1 mM Cd and a concomitant intracellular Cd content of 22.5 nmol Cd mg(-1) dw. An increased GSH synthesis under Zn-stress was only detectable for Va-H4 (20 mM).     

Dynamics of experimentally induced Staphylococcus epidermidis mastitis in East Friesian milk ewes

The responses of five lactating East Friesian milk ewes to experimental mammary infection with Staphylococcus epidermidis and of five control ewes were examined over a period of 10 weeks. Infection caused an influx of neutrophils into milk, the numbers of which started to rise 4 h post infection and peaked 24 h after infection. The initial response was accompanied by mild fever and mild leucopaenia in blood (8 h after infection). No other signs of systemic infection were observed. Milk appeared normal at all times, although the milk yield of infected ewes tended to decline. Staphylococci were absent in milk from four ewes at 2 d and at 3 d after infection, but re-emerged intermittently in four of five ewes at subsequent samplings. Cytokines in milk were measured by ELISA. IL-8 was elevated in infected glands at 2 h and peaked at 8 h. In the four ewes intermittently shedding bacteria, IL-8 remained elevated until the final sampling at 10 weeks. IL-1beta was transiently elevated at 1 d and 2 d and showed a pronounced peak in one sheep. Milk samples from this ewe were bacteriologically negative, somatic cell count (SCC) was within the normal range and the concentrations of IL-1beta, as well as IL-8, were similiar to the control group (n=5) from 1 week after infection until the final sampling. Histological examination revealed leucocytic infiltrates in the four glands remaining infected at the end of the experiment, and a high level of CD5+ lymphocytes in three ewes. The results suggest that the relationship between the initial neutrophil influx and the proinflammatory cytokines may be responsible for determining the course of infection. Subclinical mastitis due to coagulase-negative staphylococci leads to minor changes in milk yield and milk constituents.     

On Blends of Polyamide 6 and a Hyperbranched Aramid

The hyperbranched (HB) aromatic polyamide synthesised by direct polycondensation of 5‐(4‐aminobenzoylamino)isophthalic acid (ABZAIA) has been solution‐ and melt‐ blended with polyamide 6 (PA6) incorporating different end groups. The concentration of p(ABZAIA) in PA6 has been varied from 5 to 30 wt.‐% in order to evaluate the influence of hyperbranched polymer content on blend properties. Viscosity and glass transition (T_g) data of the solution blends underlined the full miscibility between the components in the explored composition range. The miscibility was not related to any specific type of PA6 end group, thus suggesting a major role for its amide groups in interacting (presumably via hydrogen bonding) with HB functional end groups. Well‐separated powder particles have been obtained by precipitation from diluted solutions both for the neat polymers and for the blends. Also, in the case of blends prepared by melt mixing T_g linearly increased with the HB polymer content, again confirming full miscibility between the blend components. Blend characterisation, solubility tests and melt rheology supported the idea that p(ABZAIA) forms reactive blends with polyamide 6 by melt mixing. As a consequence of these reactions, the hyperbranched aramid strongly modified the rheological behaviour of PA6.

Formation of well dispersed spherical and homogeneous particles after precipitation of a PA6 dilute solution.     

Computational statistics for cell survival curves. II. Evaluation of colony-forming ability of a group of cell strains by the APL function CFAGROUP

An interactive program for the statistical analysis of groups of cell survival curves is described. Methods from linear regression are applied in the presence of repeated experiments and estimates of a common slope and its variance are obtained by weighted means and a bootstrap resampling technique.