Ion Beam Sputtering Yield Measurements by Quartz Crystal Microbalance

Quartz-crystal microbalance (QCM) has been used as a sensitive device for the measurement of small mass changes for a long ago. In fact, using QCM we can measure the differential sputtering yield profile of a material, over a hemisphere above the target, very precisely. The sputtering yield depends on properties of both the incident ions (energy, mass, and incidence angle) and the target (mass, surface binding energy, surface topography, and even the crystal orientation). In our present study, we used a highly sensitive QCM to detect the mass change of the electrode material (gold and silver) through oscillations and calculated the corresponding sputtering yields. We used two types of ions, e.g, He and Ar, in an Ultra High Vacuum (UHV) chamber using the NTI ion gun as the ion source. Our experimental observation shows significantly higher sputtering yield values than that of the theoretically calculated ones, using SRIM simulations. In addition, we observed a significant reduction in the sputtering yield values with time, for a constant ion energy bombardment. Similarly, atomic force microscopy (AFM) study shows a significant reduction in the surface roughness values for a longer period of ion bombardment. These observations suggest that surface topography affects significantly the sputtering yield values. In the presentation the details of the disparities between experimental and the modeling will be discussed

Material condition assessment with eddy current sensors

Eddy current sensors and sensor arrays are used for process quality and material condition assessment of conducting materials. In an embodiment, changes in spatially registered high resolution images taken before and after cold work processing reflect the quality of the process, such as intensity and coverage. These images also permit the suppression or removal of local outlier variations. Anisotropy in a material property, such as magnetic permeability or electrical conductivity, can be intentionally introduced and used to assess material condition resulting from an operation, such as a cold work or heat treatment. The anisotropy is determined by sensors that provide directional property measurements. The sensor directionality arises from constructs that use a linear conducting drive segment to impose the magnetic field in a test material. Maintaining the orientation of this drive segment, and associated sense elements, relative to a material edge provides enhanced sensitivity for crack detection at edges

The Role of Surface Roughness on Ion Sputtering Yield Measurements

Ion sputtering is the removal of surface atoms or molecules in a solid under energetic ion irradiation. This technique is promising for its applications in material modification and characterization. Sputtering yield, the average number of atoms removed from a sample per incident ion, is a crucial parameter in material modification. In the present study, a quartz crystal microbalance was used within an ultra-high vacuum chamber (10E-8 torr) to measure the sputtering yield of gold. An NTI-1401 ion gun was used to bombard argon and helium ions onto a gold sample. The argon and helium ions used ranged in energy from 100 – 5000 eV. Theoretical sputtering yield values were determined through simulation with Stopping and Range of Ions in Matter (SRIM) software and compared with experimentally measured values. The experimental values show a significantly higher sputtering yield for gold than that of the SRIM values; however they followed the same trend. Another observation was that for a constant ion energy bombardment the sputtering yield decreased with time. An atomic force microscopy (AFM) was performed before and after sputtering. The AFM showed that the surface of the sample became smoother after a period of ion bombardment. These observations suggest that surface topography significantly affects the sputtering yield values. The reasoning behind the discrepancy between experimental and SRIM sputtering yield values will be discussed

Effect of angiotensin receptor blockade on insulin sensitivity and endothelial function in abdominally obese hypertensive patients with impaired fasting glucose

AngII (angiotensin II) may contribute to cardiovascular risk in obesity via adverse effects on insulin sensitivity and endothelial function. In the present study, we examined the effects of ARB (angiotensin receptor blocker) therapy (losartan, 100 mg/day) on insulin sensitivity and endothelial function in 53 subjects with stage I hypertension, abdominal obesity and impaired fasting glucose. The study design was a randomized double-blinded parallel design placebo-controlled multi-centre trial of 8 weeks duration. We used the hyperinsulinaemic-euglycaemic clamp technique to measure insulin sensitivity (expressed as the 'M/I' value) and RH-PAT (reactive hyperaemia-peripheral arterial tonometry) to measure endothelial function. Additional measures included HOMA (homoeostasis model assessment)-B, an index of pancreatic β-cell function, and markers of inflammation [e.g. CRP (C-reactive protein)] and oxidative stress (e.g. F2-isoprostanes). ARB therapy did not alter insulin sensitivity [5.2 (2.7) pre-treatment and 4.6 (1.6) post-treatment] compared with placebo therapy [6.1 (2.9) pre-treatment and 5.3 (2.7) post-treatment; P value not significant], but did improve the HOMA-B compared with placebo therapy (P=0.05). ARB therapy also did not change endothelial function [RH-PAT, 2.15 (0.7) pre-treatment and 2.11 (0.7) post-treatment] compared with placebo therapy [RH-PAT, 1.81 (0.5) pre-treatment and 1.76 (0.7) post-treatment; P value not significant]. Markers of inflammation and oxidative stress were not significantly changed by ARB therapy. In conclusion, ARB therapy did not alter peripheral insulin sensitivity or endothelial function in this cohort of patients with essential hypertension, abdominal obesity and impaired fasting glucose, but did improve pancreatic β-cell function

MINDMAP : establishing an integrated database infrastructure for research in ageing, mental well-being, and the urban environment

Background: Urbanization and ageing have important implications for public mental health and well-being. Cities pose major challenges for older citizens, but also offer opportunities to develop, test, and implement policies, services, infrastructure, and interventions that promote mental well-being. The MINDMAP project aims to identify the opportunities and challenges posed by urban environmental characteristics for the promotion and management of mental well-being and cognitive function of older individuals. Methods: MINDMAP aims to achieve its research objectives by bringing together longitudinal studies from 11 countries covering over 35 cities linked to databases of area-level environmental exposures and social and urban policy indicators. The infrastructure supporting integration of this data will allow multiple MINDMAP investigators to safely and remotely co-analyse individual-level and area-level data. Individual-level data is derived from baseline and follow-up measurements of ten participating cohort studies and provides information on mental well-being outcomes, sociodemographic variables, health behaviour characteristics, social factors, measures of frailty, physical function indicators, and chronic conditions, as well as blood derived clinical biochemistry-based biomarkers and genetic biomarkers. Area-level information on physical environment characteristics (e.g. green spaces, transportation), socioeconomic and sociodemographic characteristics (e.g. neighbourhood income, residential segregation, residential density), and social environment characteristics (e.g. social cohesion, criminality) and national and urban social policies is derived from publically available sources such as geoportals and administrative databases. The linkage, harmonization, and analysis of data from different sources are being carried out using piloted tools to optimize the validity of the research results and transparency of the methodology. Discussion: MINDMAP is a novel research collaboration that is combining population-based cohort data with publicly available datasets not typically used for ageing and mental well-being research. Integration of various data sources and observational units into a single platform will help to explain the differences in ageing-related mental and cognitive disorders both within as well as between cities in Europe, the US, Canada, and Russia and to assess the causal pathways and interactions between the urban environment and the individual determinants of mental well-being and cognitive ageing in older adults.Peer reviewe

Computer Law Institute

Materials from the Computer Law Institute held by UK/CLE in May 1999

Multiple sodium channel isoforms mediate the pathological effects of Pacific ciguatoxin-1

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/Human intoxication with the seafood poison ciguatoxin, a dinoflagellate polyether that activates voltage-gated sodium channels (NaV), causes ciguatera, a disease characterised by gastrointestinal and neurological disturbances. We assessed the activity of the most potent congener, Pacific ciguatoxin-1 (P-CTX-1), on NaV1.1–1.9 using imaging and electrophysiological approaches. Although P-CTX-1 is essentially a non-selective NaV toxin and shifted the voltage-dependence of activation to more hyperpolarising potentials at all NaV subtypes, an increase in the inactivation time constant was observed only at NaV1.8, while the slope factor of the conductance-voltage curves was significantly increased for NaV1.7 and peak current was significantly increased for NaV1.6. Accordingly, P-CTX-1-induced visceral and cutaneous pain behaviours were significantly decreased after pharmacological inhibition of NaV1.8 and the tetrodotoxin-sensitive isoforms NaV1.7 and NaV1.6, respectively. The contribution of these isoforms to excitability of peripheral C- and A-fibre sensory neurons, confirmed using murine skin and visceral single-fibre recordings, reflects the expression pattern of NaV isoforms in peripheral sensory neurons and their contribution to membrane depolarisation, action potential initiation and propagation

Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity

Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria