Cognitive profiles of mild cognitive impairment with and without vascular disease.

This study examined whether the cognitive profile of subjects with mild cognitive impairment (MCI) with vascular disease differs from that of MCI subjects with no vascular disease. Consecutive MCI subjects with vascular disease (n=60) and matched MCI subjects with no vascular disease (n=60) were included in the study and were compared with healthy control subjects (n=60). The neuropsychological assessment comprised tests of speed and attention, episodic memory, visuospatial function, language, and executive function. Control subjects performed significantly better than did both MCI groups on the neuropsychological battery. MCI subjects with no vascular disease performed better overall than did MCI subjects with vascular disease, most clearly on tests of speed and attention, visuospatial function, and executive function. MCI subjects with and without vascular disease exhibited differences, both in terms of overall performance and of cognitive profiles. These differences can be largely explained by deficits in speed and attention and in executive function of the MCI subjects with vascular disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Jet‐Cooking Temperature and Ionic Strength on Size and Structure of Cationic Potato Amylopectin Starch as Measured by Asymmetrical Flow Field‐Flow Fractionation Multi‐Angle Light Scattering

Asymmetrical flow field‐flow fractionation (AsFlFFF) in combination with multi‐angle light scattering (MALS) was applied to cationic potato amylopectin (CPAP) to investigate how molar mass, root‐mean‐square (r.m.s.) radius and shape was influenced by different conditions of jet‐cooking. The effect of different jet‐cooking temperatures in the range 110°C – 140°C was studied in an excess steam jet‐cooker. This equipment is used in the industry for dissolution of starch and starch derivatives before technical application. The effect of different ionic strengths conditions was examined in the range of 10–200 mM. The weight‐average molar mass decreased from about 34×10⁷ g/mol to 2.6×10⁷ g/mol when the jet‐cooking temperature was increased from 110°C to 140°C. Concurrently the root‐mean‐square radius decreased from ca 380 nm to 90 nm. The decrease in size was reflected by a decrease in viscosity with increasing temperature. The root‐mean‐square radius was reduced when increasing the ionic strength. This decrease in size was correlated with a decrease in viscosity. Conformation and Kratky plots showed that at low ionic strength (≤ 10 mM) CPAP behaved as a flexible chain with high degree of branching, close to hyperbranching. Increase of the ionic strength gave a more compact structure and changes in the internal structure were observed as well. Consequently, by using AsFlFFF – MALS the effect of technical processing on the molar mass, molecular radius, conformational structure, and shape could be determined in a size region where standard methodology commonly fails.     

Unstable eigenmodes are possible drivers for cardiac arrhythmias

The well-organized contraction of each heartbeat is enabled by an electrical wave traversing and exciting the myocardium in a regular manner. Perturbations to this wave, referred to as arrhythmias, can lead to lethal fibrillation if not treated within minutes. One manner in which arrhythmias originate is an ill-fated interaction of the regular electrical signal controlling the heartbeat, the sinus wave, with an ectopic stimulus. It is not fully understood how and when ectopic waves are generated. Based on mathematical models, we show that ectopic beats can be characterized in terms of unstable eigenmodes of the resting state.     

Spreading dynamics of a functionalized polymer latex

Functionalized polymer nanoparticles are used as binders for inorganic materials in everyday technologies such as paper and coatings. However, the functionalization can give rise to two opposing effects: It can promote adhesion via specific interactions to the substrate, but a high degree of functionalization can also hamper spreading on substrates. Here, we studied the spreading kinetics of individual functionalized vinyl acetate-co-ethylene polymer nanoparticles on inorganic substrates by atomic force microscopy (AFM) imaging. We found that the kinetics underwent a transition from a fast initial regime to a slower regime. The transition was independent of functionalization of the particles but depended on the wettability of the substrate. Furthermore, the transition from the fast regime to the slow regime occurred at a size-dependent contact angle, leading to a h ～ a(3/2) scaling dependence between the height (h) and the width (a) of the spreading particles. Thereafter, spreading continued on a slower time scale. In the slow regime, the kinetics was blocked by a high degree of functionalization. We interpret the observations in terms of a nanoscale stick-slip transition occurring at interface stress around 6 kPa. We develop models that describe the scaling relations between the particle height and width on different substrates.     

The Volta River Project: planning,housing and resettlement in Ghana, 1950–1965

This paper investigates the housing schemes proposed in connection with the Volta River Project, Ghana, in the mid-1950s to early 1960s. The Volta River Project formed part of Kwame Nkrumah’s vision for Ghana’s modernisation and industrialisation in the wake of political independence. Three associated worker housing schemes demonstrated somewhat contradictory design and construction methods, from high specification, extensive amenities, and comprehensive servicing, through to self-build ‘core’ houses amounting to little more than single-room dwellings. The paper traces the complex and controversial history of these schemes, supplemented with findings of several field trips to the settlements in question, to unravel the value of the ‘Core Houses’ approach. The most successful project to incorporate indigenous agency and true collaboration was the semi-formal ‘Combined Area’ housing at Akosombo, a positive model for shared agency and collaboration in planning, housing, and facilities delivery. Sitting alongside the carefully manicured plan of Akosombo, with its regulated market, excellent health care and desire to set high standards of cleanliness, the Combined Area has not only provided homes for the lower-paid and labouring workers of the town, but has developed over time into a settlement where professionals and retired government workers are also now residing, not out of necessity but by choice. By actively developing their own homes, shared spaces and amenities there has developed a strong sense of ownership, community, and identity. The success and level of attachment to this settlement clearly extends beyond its material presence and through the shared experience of helping to cultivate a place of one’s own.