The pH-induced swelling and collapse of a polybase brush synthesized by atom transfer radical polymerization

We have used neutron reflectometry to characterize the swelling behaviour of brushes of poly[2-(diethyl amino)ethyl methacrylate], a polybase, as a function of pH. The brushes, synthesized by the "grafting from" method of atom transfer radical polymerization, were observed to approximately double their thickness in low pH solutions, although the pK is shifted to a lower pH than in dilute solution. The composition-depth profile obtained from the reflectometry experiments for the swollen brushes reveals a region depleted in polymer between the substrate and the extended part of the brush.

The effect of bioglass addition on mechanical and physical properties of photoactive UDMA-TEGDMA resin composites

Light curable dimethacrylate resin composites undergo free radical photopolymerisation in response to blue light (wavelength 450-500 nm) and may offer superior handling and setting characteristics for novel hard tissue repair materials. The current investigation aims to determine the optimum formulation of bisphenol-A glycidyl methacrylate and triethyleneglycoldimethacrylate (bisGMA/TEGDMA) or urethane dimethacrylate (UDMA)/TEGDMA resin mixtures and the effect of Bioglass incorporation on the rate of polymerisation (RP), degree of conversion (DC) and flexural strength (FS) of light-curable filled resin composites (FRCs). Experimental photoactive resins containing a range of bisGMA, UDMA and TEGDMA ratios and/or filled with non-silanised irregular or spherical 45S5-Bioglass (50 μm; 5-40 wt%) and/or silanised silicate glass filler particulates (0.7 μm; 50-70 wt%) were tested. RP and DC were analysed in real-time using nearinfrared spectroscopy. FS of resins and FRCs were determined using three-point flexural strength tests. UDMA/TEGDMA resins exhibited increased DC compared with bisGMA/TEGDMA resins (p<0.05). The addition of spherical particles of Bioglass had a detrimental effect on the FS (p>0.05), whereas they increased DC of UDMA/TEGDMA resins (p<0.05). Addition of irregular shaped Bioglass particles increased the FS of UDMA/TEGDMA resins up to 20 wt% Bioglass (p<0.05). The flexibility and strength conferred by the urethane group in UDMA may result in enhanced physical and mechanical properties compared with conventional resins containing bulky (bisGMA) molecules. Addition of 45S5-Bioglass with specific filler content, size and morphology resulted in enhanced mechanical and physical properties of UDMA/TEGDMA composites. © (2014) Trans Tech Publications, Switzerland.

Seasonal growth of the crustose lichen Rhizocarpon geographicum (L.) DC. in South Gwynedd, Wales

Seasonal growth was studied in the slow-growing crustose lichen Rhizocarpon geographicum (L.) DC. in an area of South Gwynedd, Wales. Radial growth rate (RGR) of a sample of 20 thalli was measured in situ at three-month intervals over 51 months on a southeast-facing rock surface. There were five periods of significant growth: July-September of 1993, 1994 and 1995, in January-March of 1996, and in April-June of 1997. In four of these periods, growth coincided with a mean temperature maximum (Tmax) over a three-month period exceeding 15°C and three of the maxima with greater than 450 sunshine hours. Two of the growth maxima coincided with periods of total rainfall exceeding 300 mm and one with greater than 50 rain days in a three-month period. There were no significant linear correlations between RGR and the climatic variables measured. However, there were significant non-linear relationships between RGR and Tmax, the mean temperature minimum (Tmin), the total number of air and ground frosts and the number of rain days in a growth period, the relationship with Tmax being the most significant. Hence, in south Gwynedd, maximum growth of R. geographicum occurs in any season although the period July-September appears to be the most favourable. Relationships between growth and climatic variables were non-linear, temperature having the most significant influence on seasonal growth. ©2006 Balaban.

Distributive tactile sensing using fibre Bragg grating sensors

Two distributive tactile sensing systems are presented, based on fibre Bragg grating sensors. The first is a onedimensional metal strip with an array of 4 sensors, which is capable of detecting the magnitude and position of a contacting load. This system is compared experimentally with a similar system using resistive strain gauges. The second is a two-dimensional steel plate with 9 sensors which is able to distinguish the position and shape of a contacting load. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact.

Medication errors in mental healthcare:a systematic review

Methods: It has been estimated that medication error harms 1-2% of patients admitted to general hospitals. There has been no previous systematic review of the incidence, cause or type of medication error in mental healthcare services. Methods: A systematic literature search for studies that examined the incidence or cause of medication error in one or more stage(s) of the medication-management process in the setting of a community or hospital-based mental healthcare service was undertaken. The results in the context of the design of the study and the denominator used were examined. Results: All studies examined medication management processes, as opposed to outcomes. The reported rate of error was highest in studies that retrospectively examined drug charts, intermediate in those that relied on reporting by pharmacists to identify error and lowest in those that relied on organisational incident reporting systems. Only a few of the errors identified by the studies caused actual harm, mostly because they were detected and remedial action was taken before the patient received the drug. The focus of the research was on inpatients and prescriptions dispensed by mental health pharmacists. Conclusion: Research about medication error in mental healthcare is limited. In particular, very little is known about the incidence of error in non-hospital settings or about the harm caused by it. Evidence is available from other sources that a substantial number of adverse drug events are caused by psychotropic drugs. Some of these are preventable and might probably, therefore, be due to medication error. On the basis of this and features of the organisation of mental healthcare that might predispose to medication error, priorities for future research are suggested.

Distributive tactile sensing using fibre bragg grating sensors

Two distributive tactile sensing systems are presented, based on fibre Bragg grating sensors. The first is a one-dimensional metal strip with an array of 4 sensors, which is capable of detecting the magnitude and position of a contacting load. This system is compared experimentally with a similar system using resistive strain gauges. The second is a two-dimensional steel plate with 9 sensors which is able to distinguish the position and shape of a contacting load. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact.

GPCR modulation by RAMPs

Our conceptual understanding of the molecular architecture of G-protein coupled receptors (GPCRs) has transformed over the last decade. Once considered as largely independent functional units (aside from their interaction with the G-protein itself), it is now clear that a single GPCR is but part of a multifaceted signaling complex, each component providing an additional layer of sophistication. Receptor activity-modifying proteins (RAMPs) provide a notable example of proteins that interact with GPCRs to modify their function. They act as pharmacological switches, modifying GPCR pharmacology for a particular subset of receptors. However, there is accumulating evidence that these ubiquitous proteins have a broader role, regulating signaling and receptor trafficking. This article aims to provide the reader with a comprehensive appraisal of RAMP literature and perhaps some insight into the impact that their discovery has had on those who study GPCRs. © 2005 Elsevier Inc. All rights reserved.

Image annotation with Photocopain

Photo annotation is a resource-intensive task, yet is increasingly essential as image archives and personal photo collections grow in size. There is an inherent con?ict in the process of describing and archiving personal experiences, because casual users are generally unwilling to expend large amounts of e?ort on creating the annotations which are required to organise their collections so that they can make best use of them. This paper describes the Photocopain system, a semi-automatic image annotation system which combines information about the context in which a photograph was captured with information from other readily available sources in order to generate outline annotations for that photograph that the user may further extend or amend.

Free radical reactions in atherosclerosis; An EPR spectrometry study

The copper catalysed oxidation of homocysteine has been studied by electron paramagnetic resonance (EPR) spectroscopy and spin trapping techniques to determine the nature of free radical species formed under varying experimental conditions. Three radicals; thiyl, alkyl and hydroxyl were detected with hydroxyl being predominant. A reaction mechanism is proposed involving Fenton chemistry. Inclusion of catalase to test for intermediate generation of hydrogen peroxide showed a marked reduction in amount of hydroxyl radical generated. In contrast, the addition of superoxide dismutase showed no significant effect on the level of hydroxyl radical formed. Enhanced radical formation was observed at higher levels of oxygen, an effect which has consequences for differential oxygen levels in arterial and venous systems. Implications are drawn for a higher incidence of atherosclerotic plaque formation in arteries versus veins. © 2006 - IOS Press and the authors. All rights reserved.

The use of proteomic techniques to explore the holistic effects of nutrients in vivo

The availability of ‘omics’ technologies is transforming scientific approaches to physiological problems from a reductionist viewpoint to that of a holistic viewpoint. This is of profound importance in nutrition, since the integration of multiple systems at the level of gene expression on the synthetic side through to metabolic enzyme activity on the degradative side combine to govern nutrient availability to tissues. Protein activity is central to the process of nutrition from the initial absorption of nutrients via uptake carriers in the gut, through to distribution and transport in the blood, metabolism by degradative enzymes in tissues and excretion through renal tubule exchange proteins. Therefore, the global profiling of the proteome, defined as the entire protein complement of the genome expressed in a particular cell or organ, or in plasma or serum at a particular time, offers the potential for identification of important biomarkers of nutritional state that respond to alterations in diet. The present review considers the published evidence of nutritional modulation of the proteome in vivo which has expanded exponentially over the last 3 years. It highlights some of the challenges faced by researchers using proteomic approaches to understand the interactions of diet with genomic and metabolic–phenotypic variables in normal populations.

Plaques and tangles and the pathogenesis of Alzheimer's disease

Since the earliest descriptions, senile plaques (SP) and neurofibrillary tangles (NFT) have been regarded as the pathological hallmarks of Alzheimer's disease (AD). Consequently, studies of the morphology, distribution, and molecular composition of SP and NFT have played an important role in developing theories as to the pathogenesis of AD; the most important being the 'Amyloid Cascade Hypothesis (ACH)'. Nevertheless, the significance of SP and NFT to the pathogenesis of AD remains controversial. This review examines three questions: 1) is there a relationship between the lesions and the degree of clinical dementia, 2) is the pathogenesis of the NFT linked to that of the SP, and 3) what is the relationship of SP and NFT to the pathogenesis of AD? These questions are discussed with reference to the morphology and molecular composition of SP and NFT, the effects of gene mutations, studies of head injury patients, experimental studies involving brain lesions and transgenes, and the degeneration of specific anatomical pathways. It was concluded that SP and NFT are not closely related to the developing dementia in AD, arise as relatively independent lesions, and may be the products of a degenerative process rather than being their cause.

Measuring the spatial arrangement patterns of pathological lesions in histological sections of brain tissue

The development of abnormal protein aggregates in the form of extracellular plaques and intracellular inclusions is a characteristic feature of many neurodegenerative diseases such as Alzheimer's disease (AD), Creutzfeldt-Jakob disease (CJD) and the fronto-temporal dementias (FTD). An important aspect of a pathological protein aggregate is its spatial topography in the tissue. Lesions may not be randomly distributed within a histological section but exhibit spatial pattern, a departure from randomness either towards regularity or clustering. Information on the spatial pattern of a lesion may be useful in elucidating its pathogenesis and in studying the relationships between different lesions. This article reviews the methods that have been used to study the spatial topography of lesions. These include simple tests of whether the distribution of a lesion departs significantly from random using randomized points or sample fields, and more complex methods that employ grids or transects of contiguous fields and which can detect the intensity of aggregation and the sizes, distribution and spacing of the clusters. The usefulness of these methods in elucidating the pathogenesis of protein aggregates in neurodegenerative disease is discussed.