Assessment of the minimalist approach to computer user documentation

The minimalist approach (Carroll, 1990a) advocates the development of a radically different type of manual when compared to a conventional one. For example, the manual should proceed almost directly to procedural skills development rather than building a conceptual model first. It ought to focus on authentic tasks practised in context, as opposed to mock exercises and isolated practice. In addition, it should stimulate users to exploit their knowledge and thinking, as opposed to imposing the writer's view and discussing everything that users should see or know.

In the first part of the paper the construction of a tutorial based on the minimalist principles is described. A parallel is drawn with constructivism with which minimalism shares important notions of instruction. In the second part, an experiment is described in which the minimal manual was tested against a conventional one. The outcome favoured the new manual. For example, minimal manual users completed about 50% more tasks successfully on a performance test and displayed significantly more self-reliance (e.g. more self-initiated error-recoveries, and fewer manual consultations).     

The actin content of different muscles from beef and pork

In the literature 3-methylhistidine (3-MeHis) is mentioned as a parameter for the determination of meat content. Because of the variable molar ratio of 3-MeHis in the myofibrillar protein myosin, this indicator cannot be used without some restriction. However, the content of 3-MeHis in the myofibrillar protein actin is constant. Moreover, actin is relatively heat-stable in comparison with other muscle proteins. These facts made actin an interesting parameter for determination of the meat (protein) content of heated and raw meat products.

Fast protein liquid chromatography (FPLC) was used to separate from a meat extract an actin-containing fraction without myosin. The actin content of the meat was calculated from its content in the fraction. The latter was determined by means of a 3-MeHis method.

Several muscles of the beef and pig carcass were examined for their actin contents. Generally, the actin values were comparable with the data reported in the literature.

The influence of heat treatment was also studied on one type of beef muscle. The determined actin content was not affected up to a temperature of 85°C.     

The Simultaneous Isomerization and Hydrogenation of Glucose in Alkali Solutions

The kinetics of the simultaneous isomerization and hydrogenation of glucose are studied, and the experimental results are described with a simplified reaction model. By simulating the course of the reactions with a computer the rate constants were determined, and the energies of activation were calculated. From an Arrhenius plot the apparent isomerization activation energies were deduced. Under the experimental conditions a yield of 27% mannitol was obtained starting from glucose. Higher yields can be obtained at low temperatures and low catalyst concentrations.     

Determining the Efficacy of a Submersible in situ Fluorometric Device for Cyanobacteria Monitoring Coalesced with Total Suspended Solids Characteristic of Lowland Reservoirs

The purpose of this study was to ascertain the effect of turbid water on a fluourometric device designed to detect phycocyanin and chlorophyll a in cyanobacteria cells in vivo. Cell densities corresponding to the Blue Green Algae Alert levels endorsed by the Australian National Health and Medical Research Council and adopted by numerous water resource managers were coalesced with a range of total suspended solids at defined gradients characteristic of lowland freshwater ecosystems. The parameters of interest were phycocyanin and chlorophyll a. Microcystis aeruginosa was the experimental organism used to establish cell densities consistent with the three‐stage alert level framework. We found phycocyanin to be an effective measure for detecting M. aeruginosa at concentrations prescribed within the cyanobacterial alert levels (Green, Amber and Red) in turbid waters up to 200 Nephelometric Turbidity Units. Copyright © 2016 John Wiley & Sons, Ltd.     

The Evaluation of Activated Carbon in the Purification of Starch-based Sweeteners

Activated carbon is used in the manufacture of starch-based sweeteners such as glucose syrup, dextrose and isoglucose (HFCS) for purification and decolorization of these products. In this contribution the main production processes for activated carbon, that is steam activation and chemical activation are viewed, and the adsorptive properties of the resulting carbons are explained, based on standard adsorption tests (benzene adsorption, molasses number). Then the correlation between these properties and the aspects, that are important in the purification of starch-based sweeteners is established. With the help of results from laboratory tests on glucose syrup using activated carbons with different adsorptive properties, their specific qualities are demonstrated, and criteria for the selection of an activated carbon are discussed. Finally some practical aspects of the application of activated carbon are viewed.     

New Starch Derivatives for the Coating Industry

Continuous enzyme conversion in a jet cooker offers a lot of benefits compared to batch conversion. The starch has improved binding properties and a better overall performance. Gelpermeation chromatography shows a more favourable molecular weight distribution for the continuous enzyme converted starch. Wheat starch is a valuable binder in paper coating compared to maize starch and potato starch, when the conversion happens in the right way; continuous jet cooking gives the best results. Modified starches, such as Mylbond AC, an esterified starch, are very suitable as cobinder in topcoat applications. They show excellent binding properties and react faster with insolubilizers than oxidized enzyme converted starch, as shown by DSC measurements.     

Preparation and Calcium Complexation Properties of a Series of Oxidized Polysaccharides. Structural and Conformational Effects

A number of polysaccharides of the starch type, including maltodextrins and cyclodextrins and some other well-known polysaccharides have been oxidized by periodate/chlorite (two-step method) or hypochlorite (one-step method), yielding ring-opened polycarboxylates. The oxidation products from the starch type show by far the best calcium complexing properties and have potential application as phosphate substitutes in detergent formulations. A relatively sharp increase in calcium complexing ability is observed at a degree of polymerization of about ten, whereas just a slight further improvement occurs at higher degrees of polymerization. This phenomenon is explained by the formation of helix structures which contain efficient Ca(II) complexing sites. This idea is supported by ¹⁷O NMR measurements showing that oxidized starch type compounds with m > 10 behave as heptadentate ligands.     

SARS-CoV-2 Spike Protein and Mouse Coronavirus Inhibit Biofilm Formation by Streptococcus pneumoniae and Staphylococcus aureus

The presence of co-infections or superinfections with bacterial pathogens in COVID-19 patients is associated with poor outcomes, including increased morbidity and mortality. We hypothesized that SARS-CoV-2 and its components interact with the biofilms generated by commensal bacteria, which may contribute to co-infections. This study employed crystal violet staining and particle-tracking microrheology to characterize the formation of biofilms by Streptococcus pneumoniae and Staphylococcus aureus that commonly cause secondary bacterial pneumonia. Microrheology analyses suggested that these biofilms were inhomogeneous soft solids, consistent with their dynamic characteristics. Biofilm formation by both bacteria was significantly inhibited by co-incubation with recombinant SARS-CoV-2 spike S1 subunit and both S1 + S2 subunits, but not with S2 extracellular domain nor nucleocapsid protein. Addition of spike S1 and S2 antibodies to spike protein could partially restore bacterial biofilm production. Furthermore, biofilm formation in vitro was also compromised by live murine hepatitis virus, a related beta-coronavirus. Supporting data from LC-MS-based proteomics of spike–biofilm interactions revealed differential expression of proteins involved in quorum sensing and biofilm maturation, such as the AI-2E family transporter and LuxS, a key enzyme for AI-2 biosynthesis. Our findings suggest that these opportunistic pathogens may egress from biofilms to resume a more virulent planktonic lifestyle during coronavirus infections. The dispersion of pathogens from biofilms may culminate in potentially severe secondary infections with poor prognosis. Further detailed investigations are warranted to establish bacterial biofilms as risk factors for secondary pneumonia in COVID-19 patients.     

Catalytic Transfer Hydrogenation of Glucose-Fructose Syrups in Alkaline Solution

Equimolar mixtures of glucose and fructose were found to undergo quantitative transfer hydrogenation yielding equal amounts of gluconic acid and of hexitols (mannitol and sorbitol). The oxidationreduction occurs in aqueous alkaline medium under nitrogen at room temperature in the presence of Pt/C or Rh/C as the catalyst. Other group VIII metals did not give satisfactory results. Both a stirred batch and a continuous flow column reactor have been applied. The influence of several reaction variables has been studied, leading to the conclusion that the rate-limiting step ist the dehydrogenation reaction of glucose into gluconic acid and chemisorbed hydrogen. Subsequently, the latter is quickly consumed by coadsorbed fructose under formation of mannitol and sorbitol (in the ratio of 1.5. – 1.9: 1). Alkaline degradation products are found to be of minor importance at temperatures ≦ 25°C.     

EXAFS investigation of the destabilization of the Mg–Ni–Ti (H) system

Ti doping destabilizes the Mg₂NiH₄ system, reducing the hydrogenation enthalpy from – 64 kJ/(mol H₂) to around – 40 kJ/(mol H₂). However, the equilibrium pressure is hardly affected, as also the entropy of reaction changes. To understand this thermodynamic behavior it is essential to understand the structure of the phases present in the Ti-doped Mg₂Ni system in metallic and hydrogenated state. We used Extended X-ray Absorption Fine Structure (EXAFS) to investigate the local coordination of Ni and Ti atoms in Mg–Ni–Ti thin films both in the as-prepared as well as in the hydrogenated state. In the as-prepared state two phases, Mg₂Ni and TiNi or TiNi₃, are formed, which transform in a single Ti-doped Mg₂NiH₄ phase in the hydrogenated state. These results are consistent with previous DFT calculations for this system.