Electron microscopy studies on the coil-to-globule transition of a polyelectrolyte in a water–acetone mixture

A high molar mass polycation poly(methacryloylethyl trimethylammonium methylsulphate), PMETMMS, dissolved in mixtures of water and acetone, was studied using light scattering during the reversible coil-to-globule transition. When the mass fraction of acetone in the solvent mixture, γ, is higher than 0.80, PMETMMS adopts a globular state but does not aggregate. The collapse of PMETMMS can also be induced by the dilution of the polymer solution, if 0.70 ≤ γ < 0.80, and the solvent composition is kept constant. The results obtained by light scattering have been confirmed using a transmission electron microscope with which the collapse of PMETMMS has been observed. At high polymer concentration and 0.70 ≤ γ < 0.80, a transient network is formed: coils strongly interact with each other via dipole–dipole interactions in a thermodynamically poor solvent. At low concentration regime when 0.70 ≤ γ < 0.80, or in solutions with the mass fraction of acetone higher than 0.80, all the PMETMMS molecules are collapsed. In the intermediate region, the collapse of PMETMMS is gradual and coils, globules, as well as fragments of the network coexist in the solution. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3337–3343, 1999     

A study of high-level managerial decision processes, with implications for MCDM research

We study six real-world major strategic decisions and discuss the role that analytic Multiple Criteria Decision Making (MCDM) models could play in helping decision makers structure and solve such problems. We have interviewed successful and well-educated managers who had access to quantitative decision models, but did not use them as part of their decision process. Our approach is a clinical one that takes a close look at the decision processes. We believe that the normative MCDM framework is oversimplified and does not always fit well with complex, real-world organizational decision processes. This may be one reason why decision tools are not used more widely for solving high-level decision problems. We believe that it would be worthwhile to revise some of the MCDM mainstream postulates and practices to make existing models and tools more suitable for practical purposes. The MCDM mainstream research has until today focused on the choice among alternatives. One should realize that MCDM models could also be used in creating alternatives, in assessing the importance of criteria, in providing the decision makers with “post-commitment support”, and as part of a devil's advocate approach.     

Towards gadget-free internet services: A roadmap of the Naked world

This paper presents a roadmap for the transition from current gadget-centric digital services towards a gadget-free services environment called the Naked world. The main idea of the Naked world is that all the services which are currently provided by gadgets will be provided by the infrastructure, thus no gadgets will be needed to use any kind of digital services. When a user in the Naked world intends to use a service, the infrastructure senses the user, the nearby intelligent surrounding launches an interactive user interface, performs identification through biometric identities, provides the service, and then closes the session when the user finishes the job. Therefore, the Naked world comprises highly intelligent and context-aware interactive environments. The vision of the Naked world is an evolution towards a user-friendly and ubiquitously available digital services, which is naturally bounded by the technological advancement. Henceforth, this paper presents the essential technologies and functional requirements along with the current and forthcoming novel technological concepts and challenges for the realization of the Naked world.     

Context matters: The impact of product type,emotional attachment and information overload on choice quality

We show that contextual variables in a Multiple Criteria Decision Making task influence choice quality. Based on an experiment we investigate the effects of product type, emotional attachment, and the amount and structure of information provided. We measured choice quality with nondominance, which is a desirable property of good choices. Regarding the product type effect, we distinguish between hedonic products that primarily are desirable due to affect, and utilitarian products, which are desirable because they are useful. When subjects with high emotional attachment make choices with hedonic products, they make fewer dominated choices than with utilitarian products. Further, we show that information overload is a relevant phenomenon in MCDM experiments. However, what matters is the quality of information, not just the quantity. When we add information that does not change the dominance relations between products, choice quality is not degraded.     

Studies on aluminium corrosion during and after HF vapour treatment

The behaviour of aluminium during anhydrous hydrofluoric acid (HF) vapour etching of silicon dioxide films deposited by different methods was studied. Silicon dioxide films were grown by plasma-enhanced chemical vapour deposition (PECVD), low-pressure chemical vapour deposition (LPCVD), and a thermally oxidizing method. The etch rate of different oxides varies a lot. Etching of PECVD oxide causes residues on the aluminium surface as LPCVD and thermal oxide do not. The origin of the residues and different preventative methods are proposed.     

Efficiency analysis to incorporate interval-scale data

We develop an approach to efficiency analysis to enable us to incorporate interval-scale data in addition to ratio-scale data. Our approach introduces a measure of inefficiency and identifies efficient units as is done in Data Envelopment Analysis. The basic idea in our approach is to find the “best” hyperplane separating the units that are better and worse than each unit. “Best” is defined in such a way that the number of not-better units is maximal. The efficiency measure is defined as a proportion of not-better units to all units. The results are invariant under a strictly increasing linear re-scaling of any input- or output-variables. Thus zeroes or negative values do not cause problems for the analysis. The approach is used to analyze the data of the research evaluation exercise recently carried out at the University of Joensuu, Finland.     

Association between visual degeneration of intervertebral discs and the apparent diffusion coefficient

The value of apparent diffusion coefficient (ADC) measurements in intervertebral disc has been studied because ADC provides an estimate of free diffusion of unbound water and could be used as a quantitative tool to estimate degenerative changes. However, the challenging nature of diffusion imaging of spine and limited numbers of subjects in earlier studies has produced contradictory findings. We aimed to determine the relation between ADC and visual degenerative changes in lumbar intervertebral discs in a sufficiently large homogeneous study group. Lumbar spines of 228 volunteer middle-aged men were MR imaged at 1.5 T including anatomic and diffusion-weighted imaging. ADC values, T2 signal intensity and height, and width of the three lowest lumbar intervertebral discs were measured and disc degeneration visually graded. The calculated average ADC of 530 measured discs was 2.01×10⁻³ mm²/s±0.29 (±S.D.). The reduction in ADC between visually normal and moderately degenerated discs was 4%. Severely degenerated discs showed 5% larger ADC values than normal discs, presumably due to free water in cracks and fissures of those discs. T2 signal intensity of the disc was significantly correlated with the ADC values, whereas other measured parameters did not show correlation. There was no evident difference in ADC between the studied anatomic lumbar levels. Because there is considerable overlap between ADC values of normal and degenerated discs, we conclude that ADC measurements of intervertebral discs, at least with current technology, have limited clinical value.     

Particle size and packing characterization by diffuse light transmission

Particle size, packing density and blend composition of glass ballotini, microcrystalline cellulose pellets and theophylline granules were studied by diffuse light transmission. Diffuse visible light was directed to the sample and the intensity of the light transmitted to the opposite side of the sample was measured through a diffusing lens using a phototransistor. Light transmission was found to decrease with decreasing particle size and with increasing packing density. There was a correlation, though somewhat irregular, between light transmission and particle size for glass ballotini and microcrystalline cellulose pellets, and a strong near-linear correlation between light transmission and particle size for theophylline granules. The effect of packing density on light transmission was significant. Differentiating the composition of binary blends of microcrystalline cellulose pellets and glass ballotini and blends of theophylline granules was found possible on the basis of light transmission. The method proposed showed potential as a rapid, simple and inexpensive analytical tool for basic process diagnostics.     

The Effectiveness of Group Therapy for Students With Mild Voice Disorders: A Controlled Clinical Trial

Previous studies of students studying to be teachers have indicated that these students commonly have voice disorders. Ideally, voice disorders should be treated before students start their work as teachers, but the resources for this treatment are often limited. This study examines whether group voice therapy is effective for teacher students. Accordingly, 20 teacher students with mild voice disorders received group voice therapy (in three small groups), whereas 20 students with similar voice disorders served as a control group and consequently did not receive voice therapy. Two out of three outcome measures (perceptual evaluation of voice quality and a questionnaire on the occurrence of vocal symptoms) indicated significant changes in the treatment group compared with the control group. No differences between groups were noted in the laryngeal status. The results suggest that group voice therapy seems to be an effective method to treat students with mild voice disorders.     

An interactive algorithm to find the most preferred solution of multi-objective integer programs

In this paper, we develop an interactive algorithm that finds the most preferred solution of a decision maker (DM) for multi-objective integer programming problems. We assume that the DM’s preferences are consistent with a quasiconcave value function unknown to us. Based on the properties of quasiconcave value functions and pairwise preference information obtained from the DM, we generate constraints to restrict the implied inferior regions. The algorithm continues iteratively and guarantees to find the most preferred solution for integer programs. We test the performance of the algorithm on multi-objective assignment, knapsack, and shortest path problems and show that it works well.