The von Karman equations for plates with residual strain

We provide a derivation of the Foppl-von Karman equations for the shape of and stresses in an elastic plate with residual strains. These might arise from a range of causes: inhomogeneous growth, plastic deformation, swelling or shrinkage driven by solvent absorption. Our analysis gives rigorous bounds on the convergence of the three dimensional equations of elasticity to the low-dimensional description embodied in the plate-like description of laminae and thus justifies a recent formulation of the problem to the shape of growing leaves. It also formalizes a procedure that can be used to derive other low-dimensional descriptions of active materials.Comment: 26 page

Kinematics and dynamics of the elliptical galaxy NGC 5266.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.In studies of triaxial elliptical galaxies, one of the least observationally studied phenomena is figure rotation. Figure rotation has important consequences for the orbital structure and could explain the survival of steep nuclear cusps. For this project, we thus wish to investigate the possibility of measuring the figure rotation of an elliptical galaxy for which the geometry is approximately known using the Tremaine-Weinberg (TW) method. Originally meant for measuring the pattern speed of barred disk galaxies, we test the validity of the method using NGC 5266, a minor-axis dust-lane elliptical. In the process, the galaxy's line-of-sight velocity distribution (LOSVD) is measured along several slit positions. Measurements of the velocity v, velocity dispersion a, skewness /J3, and kurtosis h^ are derived using the Fourier Correlation Quotient method and a Gauss-Hermite series. This work represents the most detailed stellar kinematic measurements of NGC 5266 to date and confirm that it is one of the fastest rotating elliptical galaxies known today (Varnas et al. 1987). We find a maximum velocity of about 167 km s_1 at both a PA of 274° and 304°. This is compared to a maximum of 212 ± 7kms~1 at a PA of 287° found elsewhere (Varnas et al. 1987). The TW method yields significantly different values for the pattern speed. These vary between -19 and 22kms Wcsec"1. The discrepancy between the results casts doubt on the ability to straightforwardly apply the TW method to elliptical systems, but the study provides some insight into how the method may be more successfully implemented in the future

Men-centered approaches for primary and secondary prevention of HIV/ AIDS: A scoping review of effective interventions

Approximately 65,000 people live with HIV/AIDS (PLWHA) in Canada and around 82% of declared cases (52,932 cases) of HIV and AIDS are men. Without evidence-based specific interventions, HIV will continue to spread. This scoping review aims to identify evidence on best practice programs for sexual and reproductive health promotion (i.e. HIV/AIDS) targeting men, and to document the best channels for reaching men. English and French language literature indexed in relevant electronic databases was systematically searched. This was complemented by a manual search through five periodicals specializing in men's health. A total of 6608 articles were identified and 39 articles that met all inclusion and exclusion criteria were retained in the synthesis. Three reviewers independently extracted information on: health topic (i.e. HIV/AIDS), design of services (structure and resources), modes of delivery, content of intervention and main outcomes. The preventive practices with the strongest supportive evidence included, just in time information available through electronic channels (website or cell phone). Interventions designed for men only, showed significantly greater effectiveness compared to interventions targeting both men and women. We derived practical recommendations to design an integrated evidence-based preventive intervention targeting men. © 2013 Jbilou J, et al

Improving on whole-brain radiotherapy in patients with large brain metastases: a planning study to support the AROMA clinical trial

PURPOSE: To develop a novel dose-escalated volumetric modulated arc therapy (VMAT) strategy for patients with single or multiple large brain metastases which can deliver a higher dose to individual lesions for better local control (LC), and to compare dosimetry between whole brain radiotherapy (WBRT), hippocampal-sparing whole brain radiotherapy (HS-WBRT) and different VMAT-based focal radiotherapy approaches. METHODS AND MATERIALS: We identified 20 patients with one to ten brain metastases and at least one lesion larger than 15 cm3 who had received WBRT as part of routine care. For each patient, we designed and evaluated five radiotherapy treatment plans, including WBRT, HS-WBRT and three VMAT dosing models. A dose of 20 Gy in 5 fractions was prescribed to the whole brain or target volumes depending on the plan, with higher doses to smaller lesions and dose-escalated inner planning target volumes (DE-iPTV) in VMAT plans, respectively. Treatment plans were evaluated using the efficiency index, mean dose and D0.1cc to the target volumes and organs at risk. RESULTS: Compared with WBRT, VMAT plans achieved a significantly more efficient dose distribution in brain lesions, especially with our DE-iPTV model, while minimising the dose to the normal brain and other organs at risks (OARs) (p < 0.05). CONCLUSIONS: VMAT plans obtained higher doses to brain metastases and minimised doses to OARs. Dose-escalated VMAT for larger lesions allows higher radiotherapy doses to be delivered to larger lesions while maintaining safe doses to OARs

Delivery of urethral sphincter botulinum toxin injections for treating urinary retention during the COVID19 pandemic

Aims: Urethral sphincter botulinum toxin injections is an alternative treatment for urinary retention in women with Fowler’s syndrome and when access to health services were curtailed during the Covid19 pandemic, we continued to offer treatment to prevent increased demand on catheter services due to a recurrence of urinary retention. We describe our experience delivering safe and timely treatment during this period of lockdowns and restricted access to healthcare. // Methods: We retrospectively reviewed the records of all women with Fowler’s syndrome treated with transperineal urethral sphincter botulinum toxin injection between 23rd March 2020 and 31st December 2021 in a tertiary university hospital and clinical outcomes were recorded. // Results: 15 women (mean age 35.6 ± 10.1 years) received 100U OnabotulinumtoxinA injected into the external urethral sphincter as an out-patient procedure adopting hospital infection control guidelines. 41 injections were administered in total, and 8 (53%) patients received more than 1 injection (median 2 injections/patient, median inter-injection interval 108.5 days). 10 (66.7%) patients reported improvements in urinary symptoms across 31/41 (75.6%) of injections. Side effects were reported after 21.4% of injections which were mild and transient. No patients developed Covid19 within 4 weeks of the hospital visit. // Conclusion: Real-world data shows that transperineal urethral sphincter botulinum toxin injections could be continued safely and effectively during the Covid19 pandemic. This essential outpatient service played an important role in treatment and quality of life for women with Fowler’s syndrome, and avoided an additional burden on the NHS at the time of a health crisis

Orientability and energy minimization in liquid crystal models

Uniaxial nematic liquid crystals are modelled in the Oseen-Frank theory through a unit vector field $n$. This theory has the apparent drawback that it does not respect the head-to-tail symmetry in which $n$ should be equivalent to -$n$. This symmetry is preserved in the constrained Landau-de Gennes theory that works with the tensor $Q=s\big(n\otimes n- \frac{1}{3} Id\big)$.We study the differences and the overlaps between the two theories. These depend on the regularity class used as well as on the topology of the underlying domain. We show that for simply-connected domains and in the natural energy class $W^{1,2}$ the two theories coincide, but otherwise there can be differences between the two theories, which we identify. In the case of planar domains we completely characterise the instances in which the predictions of the constrained Landau-de Gennes theory differ from those of the Oseen-Frank theory