The Kinetics of Semiconductor Photocatalysis in Activity-Indicator Films

The kinetics of dye reduction, in photocatalyst indicator ink films on self cleaning glass, is studied with respect to dye concentration. The water-based, photocatalyst indicator inks comprised a redox dye, D-ox, a sacrificial electron donor (glycerol) and a polymer, hydroxyethyl cellulose. The dyes used were: Resazurin (Rz), dichloroindo-phenol (DCIP) and methylene blue (MB), although the latter required acidification of the ink (0.01M HCl) to make it work effectively under ambient conditions. Under anaerobic conditions, the photoreduction of each of the dyes, in an otherwise identical ink formulation, on Activ (TM) self-cleaning glass is zero-order with respect to [D-ox]. Seven commercial samples of Rz, each in a typical ink formulation, were tested on the same piece of self-cleaning glass under aerobic conditions and produced a striking range (over 280%) of different apparent activities for the glass, when there should have been none. The underlying cause of this variation in assessed activity is shown to be due to the combination of a variation in the purity of the commercial samples and the zero-order nature of the kinetics of indicator dye reduction. The relevance of this work and the latter observation, in particular to future use of these films for the rapid assessment of the activities of new and established photocatalytic films, is briefly discussed.

Social Participation and Maintaining Recommended Waist Circumference: Prospective Evidence From the English Longitudinal Study of Aging

Objectives: To investigate whether older adults participating in social activities are more likely to maintain or achieve recommended waist circumference (WC) levels. Method: A total of 4,280 older adults who participated in Wave 2 (baseline) and Wave 4 (follow-up) of the English Longitudinal Study of Ageing. WC was measured by a nurse in both study waves. Results: Participation in education, arts, music groups, evening classes, and in charitable associations was associated with maintaining recommended WC only in those men whose WC was in the recommended range at baseline. Participation in social activities was not associated with achieving recommended WC in women or men with initially large waist. Discussion: Participation in cultural and charitable activities may help in maintaining a recommended level of WC in older men with WC originally in the recommended range.

Improved Detection of Mycobacterium bovis Infection in Bovine Lymph Node Tissue Using Immunomagnetic Separation (IMS)-Based Methods

Immunomagnetic separation (IMS) can selectively isolate and concentrate Mycobacterium bovis cells from lymph node tissue to facilitate subsequent detection by PCR (IMS-PCR) or culture (IMS-MGIT). This study describes application of these novel IMS-based methods to test for M. bovis in a survey of 280 bovine lymph nodes (206 visibly lesioned (VL), 74 non-visibly lesioned (NVL)) collected at slaughter as part of the Northern Ireland bovine TB eradication programme. Their performance was evaluated relative to culture. Overall, 174 (62.1%) lymph node samples tested positive by culture, 162 (57.8%) by IMS-PCR (targeting IS6110), and 196 (70.0%) by IMS-MGIT culture. Twelve (6.9%) of the 174 culture positive lymph node samples were not detected by either of the IMS-based methods. However, an additional 78 M. bovis positive lymph node samples (26 (12.6%) VL and 54 (73.0%) NVL) were detected by the IMS-based methods and not by culture. When low numbers of viable M. bovis are present in lymph nodes (e.g. in NVLs of skin test reactor cattle) decontamination prior to culture may adversely affect viability, leading to false negative culture results. In contrast, IMS specifically captures whole M. bovis cells (live, dead or potentially dormant) which are not subject to any deleterious treatment before detection by PCR or MGIT culture. During this study only 2.7% of NVL lymph nodes tested culture positive, whereas 73% of the same samples tested M. bovis positive by the IMS-based tests. Results clearly demonstrate that not only are the IMS-based methods more rapid but they have greater detection sensitivity than the culture approach currently used for the detection of M. bovis infection in cattle.. Adoption of the IMS-based methods for lymph node testing would have the potential to improve M. bovis detection in clinical samples.

Improved magnetization in sputtered dysprosium thin films

50nm thick nanogranular polycrystalline dysprosium thin films have been prepared via ultra-high vacuum DC sputtering on SiO2 and Si wafers. The maximum in-plane spontaneous magnetization at T = 4K was found to be µ₀M_S,4K^(C) = (3.28±0.26)T for samples deposited on wafers heated to 350°C with a Neel point of T_N^(C) = (173±2)K and a ferromagnetic transition at T_C^(C) = (80±2)K, measured via zero-field-cooled – field-cooled magnetization measurements, close to single-crystal values. The slightly reduced magnetization is explained in the light of a metastable face-centered cubic crystal phase which occurred at the seed interface and granularity related effects, that are still noticeably influential despite an in-plane magnetic easy axis. As deposited samples showed reduced magnetization of µ₀M_S,4K^(A) = (2.26±0.18)T, however their ferromagnetic transition shifted to a much higher temperature of T_C^(A) = (172±2)K and the antiferromagnetic phase was completely suppressed probably as a result of strain.

MFM imaging of micron-sized permalloy ellipses

The magnetic domain structure of micron-sized elliptic permalloy elements has been studied by magnetic force microscope (MFM) measurements, and has been compared to results from micromagnetic simulations. The elements all have the same aspect ratio, whereas the inter-elemental distance has been varied. Both the zero-field states and in field domain configurations have been studied. In zero-applied field, two different stable flux-closure states were found in both the MFM measurements and in the simulations. The different stable domain states occur as a result of minute differences in the local magnetic environment occurring during the demagnetization process. (C) 2004 Elsevier B.V. All rights reserved.

Reactive dye adsorption onto a novel mesoporous carbon

A new mesoporous carbon (MCSG60) was developed using an inexpensive commercial mesoporous silica gel as a template and sucrose as the carbon source. The surface area, porosity and density of the carbon were determined. The material possesses a high specific surface area and pore volume accessible for most typical aqueous pollutants. The adsorbent material was tested in a batch dye adsorption system. The behaviour of three reactive dyes adsorbed onto MCSG60 was evaluated (Naphthol Blue Black, NBB; Reactive Black 5, RB5; and Remazol Brilliant Blue R, RBBR). The maximum adsorption capacities obtained for the dyes were: 270. mg/g for NBB; 270. mg/g for RB5; and 280. mg/g for RBBR. Kinetic studies indicated that the adsorption process onto the mesoporous carbon was rapid and that equilibrium was reached in less than 1. h for all the dye systems investigated. Further batch experiments showed MCSG60 successfully adsorbed the dyes over a wide pH range and at low adsorbate concentration. The adsorption potential of MCSG60 for dye removal was further evaluated using a fixed-bed adsorption column. © 2013 Elsevier B.V.

On thin ice: surface order and disorder during pre-melting

The effect of temperature on the structure of the ice Ih (0001) surface is considered through a series of molecular dynamics simulations on an ice slab. At relatively low temperatures (200K) a small fraction of surface self-interstitials (i.e. admolecules) appear that are formed exclusively from molecules leaving the outermost bilayer. At higher temperatures (ca. 250 K), vacancies start to appear in the inner part of the outermost bilayer exposing the underlying bilayer and providing sites with a high concentration of the dangling hydrogen bonds. Around 250-260 K aggregates of molecules formed on top of the outermost bilayer from self-interstitials become more mobile and have diffusivities approaching that of liquid water. At similar to 270-280 K the inner bilayer of one surface noticeably destructures and it appears that at above 285 K both surfaces are melting. The observed disparity in the onset of melting between the two sides of the slab is rationalised by considering the relationship between surface energy and the spatial distribution of protons at the surface; thermodynamic stability is conferred on the surface by maximising separations between dangling protons at the crystal exterior. Local hotspots associated with a high dangling proton density are suggested to be susceptible to pre-melting and may be more efficient at trapping species at the external surface than regions with low concentrations of protons thus potentially helping ice particles to catalyse reactions. A preliminary conclusion of this work is that only about 10-20 K below the melting temperature of the particular water potential employed is major disruption of the crystalline lattice noted which could be interpreted as being "liquid", the thickness of this film being about a nanometre.

Testate amoebae (thecamoebians) as water quality indicators in lakes: development of a modern distributional dataset from the Greater Toronto Area

Thecamoebians were examined from 123 surface sediment samples collected from 45 lakes in the Greater Toronto Area (GTA) and the surrounding region to i) elucidate the controls on faunal distribution in modern lake environments; and ii) to consider the utility of thecamoebians in quantitative studies of water quality change. This area was chosen because it includes a high density of lakes that are threatened by urban development and where water quality has deteriorated locally as a result of contaminant inputs, particularly nutrients. Canonical Correspondence analysis (CCA) and a series of partial CCAs were used to examine species-environment relationships. Twenty-four environmental variables were considered, including water properties (e.g. pH, DO, conductivity), substrate characteristics, nutrient loading, and environmentally available metals. The thecamoebian assemblages showed a strong association with Olsen's Phosphorus, reflecting the eutrophic status of many of the lakes, and locally to elevated conductivity measurements, which appear to reflect road salt inputs associated with winter de-icing operations. A transfer function was developed for Olsen P using this training set based on weighted averaging with inverse deshrinking (WA Inv). The model was applied to infer past changes in Phosphorus enrichment in core samples from several lakes, including eutrophic Haynes Lake within the GTA. Thecamoebian-inferred changes in sedimentary Phosphorus from a 210Pb dated core from Haynes Lake are related to i) widespread introduction of chemical fertilizers to agricultural land in the post WWII era; ii) a steep decline in Phosphorous with a change in agricultural practices in the late 1970s; and iii) the construction of a golf course in close proximity to the lake in the early 1990s. This preliminary study confirms that thecamoebians have considerable potential as indicators of eutrophication in lakes and can provide an estimate of baseline conditions.

The short-term effect of topical dorzolamide compared with placebo on perimetry testing in normal subjects

Purpose. To study the effect of topical dorzolamide on retinal sensitivity in normal subjects. Methods. 20 normal subjects were prospectively randomized in a two period crossover study. Baseline threshold perimetry (HVF, program 24-2, Statpac analysis) was obtained. The study eye was randomly chosen and then was randomly assigned to receive either dorzolamide 2% or placebo one hour before repeat HVF. After at least two weeks washout the same eye was given the opposite drop one hour prior to repeat HVF. Global indices were compared using a paired T-test. Results. AFTER PLACEBO AFTER DORZOLAMIDE P-VALUE (mean±SD) (mean±SD) MD 0.12±1.4 0.16±1.4 0.82 PSD 1.83±0.6 1.66±0.4 0.04 SF 1.28±0.4 1.24±0.2 0.73 CPSD 1.05±0.9 0.84±0.6 0.35 Conclusion. In this population, topical dorzolamide had little effect on visual function.

Insulin receptor substrate-2 is expressed in kidney epithelium and up-regulated in diabetic nephropathy

Diabetic nephropathy (DN) is a progressive fibrotic condition that may lead to end-stage renal disease and kidney failure. Transforming growth factor-ß1 and bone morphogenetic protein-7 (BMP7) have been shown to induce DN-like changes in the kidney and protect the kidney from such changes, respectively. Recent data identified insulin action at the level of the nephron as a crucial factor in the development and progression of DN. Insulin requires a family of insulin receptor substrate (IRS) proteins for its physiological effects, and many reports have highlighted the role of insulin and IRS proteins in kidney physiology and disease. Here, we observed IRS2 expression predominantly in the developing and adult kidney epithelium in mouse and human. BMP7 treatment of human kidney proximal tubule epithelial cells (HK-2 cells) increases IRS2 transcription. In addition, BMP7 treatment of HK-2 cells induces an electrophoretic shift in IRS2 migration on SDS/PAGE, and increased association with phosphatidylinositol-3-kinase, probably due to increased tyrosine/serine phosphorylation. In a cohort of DN patients with a range of chronic kidney disease severity, IRS2 mRNA levels were elevated approximately ninefold, with the majority of IRS2 staining evident in the kidney tubules in DN patients. These data show that IRS2 is expressed in the kidney epithelium and may play a role in the downstream protective events triggered by BMP7 in the kidney. The specific up-regulation of IRS2 in the kidney tubules of DN patients also indicates a novel role for IRS2 as a marker and/or mediator of human DN progression.

Exploring public awareness and perceptions of palliative care: a qualitative study

Background: Research suggests that the public appear to be confused about the meaning of palliative care. Given the ageing population and associated increase in the number of patients requiring palliative care, it is vital to explore the public's understanding of this concept. Health-promoting palliative care seeks to translate hospice and palliative care ideals into broader public health practice.

Aim: To explore public perceptions of palliative care and identify strategies to raise awareness.

Design: An exploratory qualitative approach. Participants: Semi-structured telephone interviews were undertaken (N = 50) with members of the public who volunteered to participate in the study. The interviews focused on knowledge and perceptions of palliative care, expectations of palliative care services and the identification of strategies to raise public awareness of palliative care. The interviews were audio recorded and content analysed.

Results: Most participants had a general knowledge of palliative care, largely influenced by their own personal experience. They identified that palliative care was about caring for people who were dying and maintaining comfort in the last days of life. Participants expectations of services included the following: holistic support, symptom management, good communication and practical support to enable choice and carer support. Key aspects identified for promoting palliative care were the development of understanding and use of the term itself and targeted educational strategies.

Conclusion: Experience of palliative care generates understanding in the general public who also have ideas for increasing knowledge and awareness. The findings can inform policymakers about strategies to raise public awareness of palliative care.

Are there species smaller than 1 mm?

The rapid advance in genetic sequencing technologies has provided an unprecedented amount of data on the biodiversity of meiofauna. It was hoped that these data would allow the identification and counting of species, distinguished as tight clusters of similar genomes. Surprisingly, this appears not to be the case. Here, we begin a theoretical discussion of this phenomenon, drawing on an individual-based ecological model to inform our arguments. The determining factor in the emergence (or not) of distinguishable genetic clusters in the model is the product of population size with mutation rate—a measure of the adaptability of the population as a whole. This result suggests that indeed one should not expect to observe clearly distinguishable species groupings in data gathered from ultrasequencing of meiofauna.