Modelling Techniques for the Quantification of Some Electron Beam Induced Phenomena

This paper presents simulation models for quantifying the voltage contrast, cathodoluminescence and indirect specimen charging phenomena in the scanning electron microscope (SEM). The voltage contrast model comprises an electric field computation program using the finite-element approach, and a secondary electron trajectory tracking algorithm employing a linear electric field assumption. This trajectory tracking algorithm is more accurate than the conventional electron trajectory tracking algorithms which make use of a constant electric field assumption within each computation step. Using this model, results of qualitative voltage contrast effects on secondary electron trajectories in the specimen chamber of the SEM are shown. This model can also be used for quantitative voltage studies for designing low error voltage energy analysers. The cathodoluminescence (CL) model consists of programs for simulating the electron beam-specimen interaction via Monte Carlo analysis, excess carrier generation and distribution, and optical losses of the CL emission. This model has been used to simulate the CL intensity as a function of surface recombination velocity, diffusion length, and absorption coefficient. A model has also been developed to simulate indirect charging of specimens in the SEM. This model uses the finite-element method to solve for the self-consistent electric field due to the imposed boundary conditions, trapped and moving charges. Secondary electrons are tracked using the trajectory tracking scheme developed

Combined use of parallel-plate compression and finite element modeling to analyze the mechanical properties of intact porcine lens

The objective of this study is to explore the feasibility of a compression test for measuring mechanical properties of intact eye lenses using novel parallel plate compression equipment to compare the accuracy of implementing a classical Hertzian model and a newly proposed adjusted Hertzian model to calculate Young’s modulus from compression test results using finite element (FE) analysis. Parallel-plate compression tests were performed on porcine lenses. An axisymmetric FE model was developed to simulate the experimental process to evaluate the accuracy of using the classical Hertzian theory of contact mechanics as well as a newly proposed adjusted Hertzian theory model for calculating the equivalent Young’s modulus. By fitting the force-displacement relation obtained from FE simulations to both the classical and adjusted Hertzian theory model and comparing the calculated modulus to the input modulus of the FE model, the results demonstrated that the classical Hertzian theory model overestimated the Young’s modulus with a proportional error of over 10%. The adjusted Hertzian theory model produced results that are closer to original input values with error ratios all lower than 1.29%. Measurements of three porcine lenses from the parallel plate compression experiments were analyzed with resulting values of Young’s modulus of between 3.2kPa and 4.3kPa calculated. This study demonstrates that the adjusted Hertzian theory of contact mechanics can be applied in conjunction with the parallel-plate compression system to investigate the overall mechanical behavior of intact lenses

Deletion of the GABAA α2-subunit does not alter self dministration of cocaine or reinstatement of cocaine seeking

Rationale GABAA receptors containing α2-subunits are highly represented in brain areas that are involved in motivation and reward, and have been associated with addiction to several drugs, including cocaine. We have shown previously that a deletion of the α2-subunit results in an absence of sensitisation to cocaine. Objective We investigated the reinforcing properties of cocaine in GABAA α2-subunit knockout (KO) mice using an intravenous self-administration procedure. Methods α2-subunit wildtype (WT), heterozygous (HT) and KO mice were trained to lever press for a 30 % condensed milk solution. After implantation with a jugular catheter, mice were trained to lever press for cocaine (0.5 mg/kg/infusion) during ten daily sessions. Responding was extinguished and the mice tested for cue- and cocaine-primed reinstatement. Separate groups of mice were trained to respond for decreasing doses of cocaine (0.25, 0.125, 0.06 and 0.03 mg/kg). Results No differences were found in acquisition of lever pressing for milk. All genotypes acquired self-administration of cocaine and did not differ in rates of self-administration, dose dependency or reinstatement. However, whilst WT and HT mice showed a dose-dependent increase in lever pressing during the cue presentation, KO mice did not. Conclusions Despite a reported absence of sensitisation, motivation to obtain cocaine remains unchanged in KO and HT mice. Reinstatement of cocaine seeking by cocaine and cocaine-paired cues is also unaffected. We postulate that whilst not directly involved in reward perception, the α2-subunit may be involved in modulating the “energising” aspect of cocaine’s effects on reward-seeking

Skin-impedance in Fabry Disease: A prospective, controlled, non-randomized clinical study

<p>Abstract</p> <p>Background</p> <p>We previously demonstrated improved sweating after enzyme replacement therapy (ERT) in Fabry disease using the thermo-regularity sweat and quantitative sudomotor axon reflex tests. Skin-impedance, a measure skin-moisture (sweating), has been used in the clinical evaluation of burns and pressure ulcers using the portable dynamic dermal impedance monitor (DDIM) system.</p> <p>Methods</p> <p>We compared skin impedance measurements in hemizygous patients with Fabry disease (22 post 3-years of bi-weekly ERT and 5 ERT naive) and 22 healthy controls. Force compensated skin-moisture values were used for statistical analysis. Outcome measures included 1) moisture reading of the 100^threpetitive reading, 2) rate of change, 3) average of 60–110^threading and 4) overall average of all readings.</p> <p>Results</p> <p>All outcome measures showed a significant difference in skin-moisture between Fabry patients and control subjects (p < 0.0001). There was no difference between Fabry patients on ERT and patients naïve to ERT. Increased skin-impedance values for the four skin-impedance outcome measures were found in a small number of dermatome test-sites two days post-enzyme infusions.</p> <p>Conclusion</p> <p>The instrument portability, ease of its use, a relatively short time required for the assessment, and the fact that DDIM system was able to detect the difference in skin-moisture renders the instrument a useful clinical tool.</p

A comparison of laboratory and in situ methods to determine soil thermal conductivity for energy foundations and other ground heat exchanger applications

Soil thermal conductivity is an important factor in the design of energy foundations and other ground heat exchanger systems. It can be determined by a field thermal response test, which is both costly and time consuming, but tests a large volume of soil. Alternatively, cheaper and quicker laboratory test methods may be applied to smaller soil samples. This paper investigates two different laboratory methods: the steady-state thermal cell and the transient needle probe. U100 soil samples were taken during the site investigation for a small diameter test pile, for which a thermal response test was later conducted. The thermal conductivities of the samples were measured using the two laboratory methods. The results from the thermal cell and needle probe were significantly different, with the thermal cell consistently giving higher values for thermal conductivity. The main difficulty with the thermal cell was determining the rate of heat flow, as the apparatus experiences significant heat losses. The needle probe was found to have fewer significant sources of error, but tests a smaller soil sample than the thermal cell. However, both laboratory methods gave much lower values of thermal conductivity compared to the in situ thermal response test. Possible reasons for these discrepancies are discussed, including sample size, orientation and disturbance

NF-κB activation in inflammatory breast cancer is associated with oestrogen receptor downregulation, secondary to EGFR and/or ErbB2 overexpression and MAPK hyperactivation

Activation of NF-κB in inflammatory breast cancer (IBC) is associated with loss of estrogen receptor (ER) expression, indicating a potential crosstalk between NF-κB and ER. In this study, we examined the activation of NF-κB in IBC and non-IBC with respect to ER and EGFR and/or ErbB2 expression and MAPK hyperactivation. A qRT–PCR based ER signature was evaluated in tumours with and without transcriptionally active NF-κB, as well as correlated with the expression of eight NF-κB target genes. Using a combined ER/NF-κB signature, hierarchical clustering was executed. Hyperactivation of MAPK was investigated using a recently described MAPK signature (Creighton et al, 2006), and was linked to tumour phenotype, ER and EGFR and/or ErbB2 overexpression. The expression of most ER-modulated genes was significantly elevated in breast tumours without transcriptionally active NF-κB. In addition, the expression of most ER-modulated genes was significantly anticorrelated with the expression of most NF-κB target genes, indicating an inverse correlation between ER and NF-κB activation. Clustering using the combined ER and NF-κB signature revealed one cluster mainly characterised by low NF-κB target gene expression and a second one with elevated NF-κB target gene expression. The first cluster was mainly characterised by non-IBC specimens and IHC ER+ breast tumours (13 out of 18 and 15 out of 18 respectively), whereas the second cluster was mainly characterised by IBC specimens and IHC ER− breast tumours (12 out of 19 and 15 out of 19 respectively) (Pearson χ2, P<0.0001 and P<0.0001 respectively). Hyperactivation of MAPK was associated with both ER status and tumour phenotype by unsupervised hierarchical clustering using the MAPK signature and was significantly reflected by overexpression of EGFR and/or ErbB2. NF-κB activation is linked to loss of ER expression and activation in IBC and in breast cancer in general. The inverse correlation between NF-κB activation and ER activation is due to EGFR and/or ErbB2 overexpression, resulting in NF-κB activation and ER downregulation

Delivery of chlamydia screening to young women requesting emergency hormonal contraception at pharmacies in Manchester, UK: a prospective study

<p>Abstract</p> <p>Background</p> <p>More women are requesting Emergency Hormonal Contraception (EHC) at pharmacies where screening for <it>Chlamydia trachomatis </it>is not routinely offered. The objective of this study was to assess the uptake of free postal chlamydia screening by women under 25 years who requested EHC at pharmacies in Manchester, UK.</p> <p>Methods</p> <p>Six Primary Care Trusts (PCTs) that had contracted with pharmacies to provide free EHC, requested the largest EHC providers (≥ 40 doses annually) to also offer these clients a coded chlamydia home testing kit. Pharmacies kept records of the ages and numbers of women who accepted or refused chlamydia kits. Women sent urine samples directly to the laboratory for testing and positive cases were notified. Audit data on EHC coverage was obtained from PCTs to assess the proportion of clients eligible for screening and to verify the uptake rate.</p> <p>Results</p> <p>33 pharmacies participated. Audit data for 131 pharmacy months indicated that only 24.8% (675/2718) of women provided EHC were also offered chlamydia screening. Based on tracking forms provided by pharmacies for the whole of the study, 1348/2904 EHC clients (46.4%) who had been offered screening accepted a screening kit. 264 (17.6%) of those who accepted a kit returned a sample, of whom 24 (9.1%) were chlamydia-positive. There was an increase in chlamydia positivity with age (OR: 1.2 per year; 1.04 to 1.44; p = 0.015).</p> <p>Conclusion</p> <p>Chlamydia screening for EHC pharmacy clients is warranted but failure of pharmacists to target all EHC clients represented a missed opportunity for treating a well defined high-risk group.</p

The Social Relations Approach, empowerment and women factory workers in Malaysia

This article discusses the empowerment of women factory workers in Malaysia through the lens of Kabeer’s Social Relations Approach. The approach offers an institutional analysis of how gender inequality is produced and calls for the overall terms of exchange and cooperation to be shifted in women’s favour. Its application shows that Malaysian women factory workers face significant challenges, due to the character of institutions, and women’s difficulties in adopting and internalising the notion of ‘empowerment’

Mobile Health Biometrics to Enhance Exercise and Physical Activity Adherence in Type 2 Diabetes (MOTIVATE-T2D): protocol for a feasibility randomised controlled trial

Introduction Exercise and physical activity (PA) are fundamental to the treatment of type 2 diabetes. Current exercise and PA strategies for newly diagnosed individuals with type 2 diabetes are either clinically effective but unsuitable in routine practice (supervised exercise) or suitable in routine practice but clinically ineffective (PA advice). Mobile health (mHealth) technologies, offering biometric data to patients and healthcare professionals, may bridge the gap between supervised exercise and PA advice, enabling patients to engage in regular long-term physically active lifestyles. This feasibility randomised controlled trial (RCT) will evaluate the use of mHealth technology when incorporated into a structured home-based exercise and PA intervention, in those recently diagnosed with type 2 diabetes.Methods and analysis This feasibility multicentre, parallel group RCT will recruit 120 individuals with type 2 diabetes (diagnosis within 5–24 months, aged 40–75 years) in the UK (n=60) and Canada (n=60). Participants will undertake a 6-month structured exercise and PA intervention and be supported by an exercise specialist (active control). The intervention group will receive additional support from a smartwatch and phone app, providing real-time feedback and enabling improved communication between the exercise specialist and participant. Primary outcomes are recruitment rate, adherence to exercise and loss to follow-up. Secondary outcomes include a qualitative process evaluation and piloting of potential clinical outcome measures for a future RCT. Ethics and dissemination The trial was approved in the UK by the South East Scotland Research Ethics Committee 01 (20/SS/0101) and in Canada by the Clinical Research Ethics Board of the University of British Columbia (H20-01936), and is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Results will be published in peer-reviewed journals and presented at national and international scientific meetings.Trial registrationnumbers,ISRCTN14335124; ClinicalTrials.gov: NCT04653532