Strain distribution in the porcine lumbar laminae under asymmetric loading

If the articular facets of the vertebra grow in an asymmetric manner, the developed geometry causes an asymmetry of loading. When the loading environment is altered by way of increased activity, the likelihood of acquiring a stress fracture may be increased. The combination of geometric asymmetry and increased activity is hypothesised to be the precursor to the stress fracture under investigation in this study, spondylolysis. This vertebral defect is an acquired fracture with 7% prevalence in the paediatric population. This value increases to 21% among athletes who participate in hyperextension sports. Tests were carried out on porcine lumbar vertebrae, on which the effect of facet angle asymmetry was simulated by offsetting the load laterally by 7mm from the mid-point. The aim of the study is to investigate whether an increase in the coronal orientation of one facet leads to an increase in strain in the corresponding vertebral lamina. Strain in the laminae was recorded using six 3-element stacked rosette strain gauges placed bilaterally. Results show that a significant linear predictive relationship exists between load offset and average strain level in the vertebral laminae with p values of 0.006 and 0.045 for principal strains e1 and e2 on the right-hand side, and p-values of 0.009 and 0.001 for principal strains e1 and e2 on the left-hand side (R2 all .0.9). This study concludes that facet angle asymmetry does lead to a difference in strain in the vertebral laminae. Change in principal strain as a result of facet asymmetry has a linear relationship and an asymmetry threshold exists beyond which compressive strain on the more coronally oriented facet can be increased by up to 15%

Fatigue and damage of porcine pars interarticularis during asymmetric loading

If the articular facets of the vertebra grow in an asymmetric manner, the developed bone geometry causes an asymmetry of loading. When the loading environment is altered by way of increased activity, the likelihood of acquiring a stress fracture may be increased. The combination of geometric asymmetry and increased activity is hypothesised to be the precursor to the stress fracture under investigation in this study, spondylolysis. This vertebral defect is an acquired fracture with 7% prevalence in the paediatric population. This value increases to 21% among athletes who participate in hyperextension sports. Tests were carried out on porcine lumbar vertebrae, on which the effect of facet angle asymmetry was simulated by offsetting the load laterally by 7mm from the mid-point. Strain in the vertebral laminae was recorded using six 3-element stacked rosette strain gauges placed bilaterally. Specimens were loaded cyclically at a rate of 2Hz. Fatigue cycles; strain, creep, secant modulus and hysteresis were measured. The principal conclusions of this paper are that differences in facet angle lead to an asymmetry of loading in the facet joints; this in turn leads to an initial increase in strain on the side with the more coronally orientated facet. The strain amplitude, which is the driving force for crack propagation, is greater on this side at all times up to fracture, the significance of this can be observed in the increased steady state creep rate (p = 0.036) and the increase in yielding and toughening mechanisms taking place, quantified by the force-displacement hysteresis (p = 0.026)

Using the forces of hydrodynamic countercurrent chromatography for the study of bacteriophages

Bacteriophages (phages) are viruses that target bacteria, with the ability to lyse and kill host bacterial cells. Due to this, they have been of some interest as a therapeutic since their discovery in the early 1900s, but with the recent increase in antibiotic resistance, phages have seen a resurgence in attention. Current methods of isolation and purification of phages can be long and tedious, with caesium chloride concentration gradients the gold standard for purifying a phage fraction. Isolation of novel phages requires centrifugation and ultrafiltration of mixed samples, such as water sources, effluent or faecal samples etc, to prepare phage filtrates for further testing. We propose countercurrent chromatography as a novel and alternative approach to use when studying phages, as a scalable and high-yield method for obtaining phage fractions. However, the full extent of the usefulness and resolution of separation with this technique has not been researched; it requires optimization and ample testing before this can be revealed. Here we present an initial study to determine survivability of two phages, T4 and ϕX174, using only water as a mobile phase in a Spectrum Series 20 HPCCC. Both phages were found to remain active once eluted from the column. Phages do not fully elute from the column and sodium hydroxide is necessary to flush the column between runs to deactivate remaining phages

Creativity and Care in times of crisis: an analysis of the challenges of the COVID-19 virus experienced by social work students in practice placement

COVID-19 has had a significant impact on the way social work responds to a wide range of social issues facing PWLE (People with Learned Experience). This paper evaluates a small-scale research project conducted by academics teaching on a United Kingdom (UK) social work degree programme. It explores the experience of students undertaking social work placements and how their practice was impacted upon by the lockdown. The focus concerns the challenges students faced when they were unable to continue their real-time practice placements and instead were asked to undertake virtual learning experiences through the use of Action Learning Sets (ALS) and Blogs. The responses indicate that the students found the use of Action Learning Sets improved their experience during a difficult period. Important lessons can be learned which can contribute to enhancing the educational experience on social work programmes in the UK. These included the recognition of the student voice in delivery, the impact of caring responsibilities, and the need, in future interventions, to directly involve People With Lived Experience in the development and delivery of such initiatives

Exogenous sex steroid hormones and asthma in females:protocol for a population-based retrospective cohort study using a UK primary care database

This work was supported by Asthma UK, grant number: AUK-IG-2016-346. BIN, INS, CRS and AS were in addition support by the Farr Institute and Asthma UK Centre for Applied Research. BIN acknowledges the support of Knut and Alice Wallenberg Foundation and the Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden.Peer reviewedPublisher PD

Hormone replacement therapy and asthma onset in menopausal women: National cohort study

© 2020 The Authors Background: There is uncertainty about the role of hormonal replacement therapy (HRT) in the development of asthma. Objective: We investigated whether use of HRT and duration of use was associated with risk of development of asthma in perimenopausal and postmenopausal women. Methods: We constructed a 17-year (from January 1, 2000, to December 31, 2016) open cohort of 353,173 women (aged 46-70 years) from the Optimum Patient Care Database, a longitudinal primary care database from across the United Kingdom. HRT use, subtypes, and duration of use; confounding variables; and asthma onset were defined by using the Read Clinical Classification System. We fitted multilevel Cox regression models to estimate hazard ratios (HRs) with 95% CIs. Results: During the 17-year follow-up (1,340,423 person years), 7,614 new asthma cases occurred, giving an incidence rate of 5.7 (95% CI = 5.5-5.8) per 1,000 person years. Compared with nonuse of HRT, previous use of any (HR = 0.83; 95% CI = 0.76-0.88), estrogen-only (HR = 0.89; 95% CI = 0.84-0.95), or combined estrogen and progestogen (HR = 0.82; 95% CI = 0.76-0.88) HRT was associated with a reduced risk of asthma onset. This was also the case with current use of any (HR = 0.79; 95% CI = 0.74-0.85), estrogen-only (HR = 0.80; 95% CI = 0.73-0.87), and combined estrogen and progestogen (HR = 0.78; 95% CI = 0.70-0.87) HRT. Longer duration of HRT use (1-2 years [HR = 0.93; 95% CI = 0.87-0.99]; 3-4 years [HR = 0.77; 95% CI = 0.70-0.84]; and ≥5 years [HR = 0.71; 95% CI = 0.64-0.78]) was associated with a dose-response reduced risk of asthma onset.Conclusion: We found that HRT was associated with a reduced risk of development of late onset asthma in menopausal women. Further cohort studies are needed to confirm these findings

Hormone Replacement Therapy and Risk of Severe Asthma Exacerbation in Perimenopausal and Postmenopausal Women : 17-Year National Cohort Study

This work was supported by Asthma UK, grant number: AUK-IG-2016-346 and Health Data Research UK. We thank Optimum Patient Care (OPC) and Observational and Pragmatic Research Institute Pte Ltd (OPRI) for making the OPCRD database (www.opcrd.co.uk) available free of charge. B. I. Nwaru acknowledges the support of Knut and Alice Wallenberg Foundation, the Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden, and the VBG Group Herman Krefting Foundation on Asthma and Allergy. A. Sheikh acknowledges support of Health Data Research UK (BREATHE).Peer reviewedPublisher PD

Is shape in the eye of the beholder? Assessing landmarking error in geometric morphometric analyses on live fish

Geometric morphometrics is widely used to quantify morphological variation between biological specimens, but the fundamental influence of operator bias on data reproducibility is rarely considered, particularly in studies using photographs of live animals taken under field conditions. We examined this using four independent operators that applied an identical landmarking scheme to replicate photographs of 291 live Atlantic salmon (Salmo salar L.) from two rivers. Using repeated measures tests, we found significant inter-operator differences in mean body shape, suggesting that the operators introduced a systematic error despite following the same landmarking scheme. No significant differences were detected when the landmarking process was repeated by the same operator on a random subset of photographs. Importantly, in spite of significant operator bias, small but statistically significant morphological differences between fish from the two rivers were found consistently by all operators. Pairwise tests of angles of vectors of shape change showed that these between-river differences in body shape were analogous across operator datasets, suggesting a general reproducibility of findings obtained by geometric morphometric studies. In contrast, merging landmark data when fish from each river are digitised by different operators had a significant impact on downstream analyses, highlighting an intrinsic risk of bias. Overall, we show that, even when significant inter-operator error is introduced during digitisation, following an identical landmarking scheme can identify morphological differences between populations. This study indicates that operators digitising at least a sub-set of all data groups of interest may be an effective way of mitigating inter-operator error and potentially enabling data sharing

Development of a Scalable and Sustainable High Performance CounterCurrent Chromatography (HPCCC) Purification for Spinosyn A and Spinosyn D from Spinosad

© 2017 American Chemical Society. A high-performance countercurrent chromatography (HPCCC) process was developed as a more efficient and sustainable alternative to reverse phase high-performance liquid chromatography (RP-HPLC) for the pilot-scale purification of the naturally occurring fermentation-derived insecticides, spinosyn A and spinosyn D, the major components of spinosad insecticide. While on pilot scale HPCCC and RP-HPLC both gave > 99% purities and comparable combined recoveries of 77% and 83%, respectively, HPCCC was much more efficient and sustainable by producing a 60% higher productivity, 11 times higher solute loading, 96% savings in stationary phase costs, and 42% reduction in solvent usage. The increase in productivity and reduction in solvent usage further reduced waste recycle and disposal costs, thus presenting significantly less environmental impact compared to RP-HPLC separations. The use of mixing on demand for a solvent system at the preparative scale allowed a complete automation with minimized solvent consumption