Optimization of the processing of HNBR/organoclay nanocomposite

In the current investigation, rubber/clay nanocomposites were prepared by two different methods using hydrogenated nitrile butadiene rubber (HNBR) and the organoclay namely Cloisite 15A (C15A). A new novel approach involving swelling of C15A by ulltrasonication in HNBR solution has been carried out for improving the exfoliation and compatibilization of organoclays with HNBR matrix. With the addition of 5phr of clay, the elongation at break and tear strength improved by 16% and 24% respectively. The effect of coupling agents namely amino functional silane and tetrasulfido silane on the nanocomposites have been investigated. The elongation at break and tear strength improved by 46% and 77% respectively with the use of silanes. The improvement in the mechanical properties attributes to improved interaction between the organoclays and HNBR matrix. This interaction has been studied by X-ray diffraction and transmission electron microscope. Pre-dispersion technique clearly suggests very good improvement in the dispersion and properties due to better filler-rubber compatibility. © 2010 American Institute of Physics.

A method to reconstruct patient-specific proximal femur surface models from planar pre-operative radiographs

Three-dimensional reconstruction from volumetric medical images (e.g. CT, MRI) is a well-established technology used in patient-specific modelling. However, there are many cases where only 2D (planar) images may be available, e.g. if radiation dose must be limited or if retrospective data is being used from periods when 3D data was not available. This study aims to address such cases by proposing an automated method to create 3D surface models from planar radiographs. The method consists of (i) contour extraction from the radiograph using an Active Contour (Snake) algorithm, (ii) selection of a closest matching 3D model from a library of generic models, and (iii) warping the selected generic model to improve correlation with the extracted contour.

This method proved to be fully automated, rapid and robust on a given set of radiographs. Measured mean surface distance error values were low when comparing models reconstructed from matching pairs of CT scans and planar X-rays (2.57–3.74 mm) and within ranges of similar studies. Benefits of the method are that it requires a single radiographic image to perform the surface reconstruction task and it is fully automated. Mechanical simulations of loaded bone with different levels of reconstruction accuracy showed that an error in predicted strain fields grows proportionally to the error level in geometric precision. In conclusion, models generated by the proposed technique are deemed acceptable to perform realistic patient-specific simulations when 3D data sources are unavailable.

Human B cell colony growth from pre-B cells in vitro

We describe a simple one-step technique for the growth of human B cell colonies in semi-solid agar in vitro. This method used conditioned medium from the human plasmacytoma cell line LICR-LON-H My 2 as a source of stimulating activity. A linear relationship exists between the number of B cells seeded and the number of colonies formed (r = 0.95). Most colony forming cells, approximately 1 in 500 of B cells seeded, lack surface immunoglobulin, possess Fc receptors and mark with the Leu 12 monoclonal antibody. Cells within developing colonies are found to have cytoplasmic IgM, IgA and IgG depending on the length of time in culture.

Pre-intravitrael injection preparation: endophthalmitis prevention and the importance of povidone-iodine

Despite adherence to strict standards of care in preparation for intravitreal injections, endophthalmitis can still occur. This article focuses on endophthalmitis and the importance of povidone-iodine in pre-procedure antisepsis. An overview of endophthalmitis and an examination of the benefits of povidone-iodine in ocular aseptic technique for the prevention of post-procedure endophthalmitis are provided. The misconceptions that patients and health practitioners may have in relation to povidone-iodine hypersensitivity are also explored.

Optimisation of a two-liquid component pre-filled acrylic bone cement system: A design of experiments approach to optimise cement final properties

The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery—acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery.

Ultrasound entropy may be a new non-invasive measure of pre-clinical vascular damage in young hypertensive patients

Background: The identification of pre-clinical microvascular damage in hypertension by non-invasive techniques has proved frustrating for clinicians. This proof of concept study investigated whether entropy, a novel summary measure for characterizing blood velocity waveforms, is altered in participants with hypertension and may therefore be useful in risk stratification.

Methods: Doppler ultrasound waveforms were obtained from the carotid and retrobulbar circulation in 42 participants with uncomplicated grade 1 hypertension (mean systolic/diastolic blood pressure (BP) 142/92 mmHg), and 26 healthy controls (mean systolic/diastolic BP 116/69 mmHg). Mean wavelet entropy was derived from flow-velocity data and compared with traditional haemodynamic measures of microvascular function, namely the resistive and pulsatility indices.

Results: Entropy, was significantly higher in control participants in the central retinal artery (CRA) (differential mean 0.11 (standard error 0.05 cms(-1)), CI 0.009 to 0.219, p 0.017) and ophthalmic artery (0.12 (0.05), CI 0.004 to 0.215, p 0.04). In comparison, the resistive index (0.12 (0.05), CI 0.005 to 0.226, p 0.029) and pulsatility index (0.96 (0.38), CI 0.19 to 1.72, p 0.015) showed significant differences between groups in the CRA alone. Regression analysis indicated that entropy was significantly influenced by age and systolic blood pressure (r values 0.4-0.6). None of the measures were significantly altered in the larger conduit vessel.

Conclusion: This is the first application of entropy to human blood velocity waveform analysis and shows that this new technique has the ability to discriminate health from early hypertensive disease, thereby promoting the early identification of cardiovascular disease in a young hypertensive population.

Preparing medical students for normal birth: an interactive workshop by pre-registration midwifery students.

There is an increasing recognition of the need to improve inter professional relationships within clinical practice (DoH, 2001). Evidence supports the assertion that health care professionals who are able to communicate and work effectively together and who have a mutual respect and understanding for one another’s roles will provide a higher standard of care (McPherson et al, 2001; Begley, 2008). Providing inter professional education within a University setting offers an opportunity for a non-threatening learning environment where students can develop confidence and build collaborative working relationships with one another (Saxell et al, 2009).
An inter-professional education initiative was developed in Queen’s University Belfast within the Schools of Nursing and Midwifery and Medicine and piloted in 2014. The aim of the collaboration was to introduce concepts of normal labour and birth to fourth year medical students prior to their obstetric and gynaecological placement in hospital. The teaching staff felt this would be an excellent opportunity for final year pre-registration midwifery students to demonstrate their knowledge and understanding on normality in labour and birth by preparing interactive workshops with the medical students. The midwifery students were provided with an outline agenda in relation to content for the workshop, but then were allowed creative licence with regard to delivery of the workshop. The workshops consisted of approximately 4 midwifery students to 12 medical students. Resources such as birthing balls, birth mannequins, dolls and pelvises were available to the students to increase interactivity. Significant emphasis was placed upon the importance of relationship building with women in labour and the concept of being ‘with woman’ was core to all elements of teaching. Midwifery students undertook acting roles such as the labouring woman, partner or a midwife role and acted out mini scenarios such as contacting for advice about early labour; positions for labour or positions for birth. Medical students were prompted to vocalise about their feelings towards labour and birth and encouraged to think about their role within the birth setting.
Preliminary evaluations of the workshops have been extremely positive from both the midwifery students and the medical students. The midwifery students have commented on the enjoyable aspects of team working for preparing for the workshop and also the confidence gained from teaching the medical students. The medical students have evaluated the teaching by the midwifery students positively and felt that it lowered their anxiety going into the labour setting. A number of midwifery and medical students have subsequently worked with one another within the practice setting which has been recognised as beneficial. Both Schools have recognised the benefits of this form of inter professional education and have subsequently made a commitment to embed it within each curriculum.

Validation of a high-throughput immunobead array technique for multiplex detection of three foodborne pathogens in chicken products

This study rigorously evaluated a previously developed immunobead array method to simultaneously detect three important foodborne pathogens, Campylobacter jejuni, Listeria monocytogenes, and Salmonella spp., for its actual application in routine food testing. Due to the limitation of the detection limit of the developed method, an enrichment step was included in this study by using Campylobacter Enrichment Broth for C. jejuni and Universal Pre-enrichment Broth for L. monocytogenes and Salmonella spp.. The findings show that the immunobead array method was capable of detecting as low as 1 CFU of the pathogens spiked in the culture media after being cultured for 24 hours for all three pathogens. The immunobead array method was further evaluated for its pathogen detection capabilities in ready-to-eat (RTE) and ready-to-cook (RTC) chicken samples and proven to be able to detect as low as 1 CFU of the pathogens spiked in the food samples after being cultured for 24 hours in the case of Salmonella spp., and L. monocytogenes and 48 hours in the case of C. jejuni. The method was subsequently validated with three types of chicken products (RTE, n=30; RTC, n=20; raw chicken, n=20) and was found to give the same results as the conventional plating method. Our findings demonstrated that the previously developed immunobead array method could be used for actual food testing with minimal enrichment period of only 52 hours, whereas the conventional ISO protocols for the same pathogens take 90-144 hours. The immunobead array was therefore an inexpensive, rapid and simple method for the food testing.

Gene scanning of VDJH-amplified segments is a clinically relevant technique to detect contaminating tumor cells in the apheresis products of multiple myeloma patients undergoing autologous peripheral blood stem cell transplantation.

Contaminating tumour cells in apheresis products have proved to influence the outcome of patients with multiple myeloma (MM) undergoing autologous stem cell transplantation (APBSCT). The gene scanning of clonally rearranged VDJ segments of the heavy chain immunoglobulin gene (VDJH) is a reproducible and easy to perform technique that can be optimised for clinical laboratories. We used it to analyse the aphereses of 27 MM patients undergoing APBSCT with clonally detectable VDJH segments, and 14 of them yielded monoclonal peaks in at least one apheresis product. The presence of positive results was not related to any pre-transplant characteristics, except the age at diagnosis (lower in patients with negative products, P = 0.04). Moreover, a better pre-transplant response trended to associate with a negative result (P = 0.069). Patients with clonally free products were more likely to obtain a better response to transplant (complete remission, 54% vs 28%; >90% reduction in the M-component, 93% vs 43% P = 0.028). In addition, patients transplanted with polyclonal products had longer progression-free survival, (39 vs 19 months, P = 0.037) and overall survival (81% vs 28% at 5 years, P = 0.045) than those transplanted with monoclonal apheresis. In summary, the gene scanning of apheresis products is a useful and clinically relevant technique in MM transplanted patients.

Validation of immunocytochemistry as a morphomolecular technique

Immunocytochemistry (ICC) is a long-established means for clinical laboratories to investigate material for which it is difficult to obtain tissue samples. Unlike immunohistochemistry (IHC), the cells do not retain surrounding tissue environment/architecture. This can be of benefit in that fixation is often immediate and rapid, protecting the cells. Although fixation is frequently observed as the main preanalytic variable of test quality, all cytology preanalytic factors should be identified and controlled. In addition, the validation of ICC should take the same rigorous approach that other molecular pathology techniques follow. A three-step validation protocol is offered here. The end result is a comprehensive, morphomolecular approach to ICC, with an emphasis on therapeutic ICC.