Controlled adhesion, membrane pinning and vesicle transport by Janus particles

The interactions between biomembranes and particles are key to many applications, but the lack of controllable model systems to study them limits the progress in their research. Here, we describe how Janus polystyrene microparticles, half coated with iron, can be partially engulfed by artificial cells, namely giant vesicles, with the goals to control and investigate their adhesion and degree of encapsulation. The interaction between the Janus particles and these model cell membrane systems is mediated by electrostatic charge, offering a further mode of modulation in addition to the iron patches. The ferromagnetic particle coatings also enable the ability to manipulate and transport the vesicles by magnetic fields

Productivity of Osprey, Pandion haliaetus, Nesting on Natural and Artificial Structures in the Kawartha Lakes, Ontario, 1991-2001

Ospreys (Pandion haliaetus) declined throughout the Great Lakes basin during the 1950s to 1970s due to usage of organochlorine pesticides. Following the banning of DDT in 1972, artificial elevated nest structures were erected in the Kawartha Lakes region of south-central Ontario to aid in their recovery. As the population grew, large stumps of flooded trees, < 1 m above the surface of the water became important nesting sites, despite their propensity to flood in turbulent weather conditions. We compared the productivity of Ospreys among nest substrates and longevity of the nests in this area from 1991 to 2001. Of 260 individual nesting attempts made over the 11 years, 57% used man-made structures, primarily either quadrupod nesting platforms or utility poles. Of nests on natural substrates, stump nests accounted for 37% of total nesting attempts; elevated tree nests were relatively uncommon (6%). Productivity of stump nests was significantly greater than that of artificial or tree nests (1.48 versus 1.16 and 0.73 chicks produced per occupied nest, respectively). Nevertheless, survivorship of stump nests was less than that of platform nests after 3 years of age, as high water levels, storms or winter ice activity destroyed some of these low nests between breeding seasons. Ospreys were able to attain greater productivity in these stump nests than on man-made nesting substrates

Pipeline network features and leak detection by cross-correlation analysis of reflected waves

This paper describes progress on a new technique to detect pipeline features and leaks using signal processing of a pressure wave measurement. Previous work (by the present authors) has shown that the analysis of pressure wave reflections in fluid pipe networks can be used to identify specific pipeline features such as open ends, closed ends, valves, junctions, and certain types of bends. It was demonstrated that by using an extension of cross-correlation analysis, the identification of features can be achieved using fewer sensors than are traditionally employed. The key to the effectiveness of the technique lies in the artificial generation of pressure waves using a solenoid valve, rather than relying upon natural sources of fluid excitation. This paper uses an enhanced signal processing technique to improve the detection of leaks. It is shown experimentally that features and leaks can be detected around a sharp bend and up to seven reflections from features/ leaks can be detected, by which time the wave has traveled over 95 m. The testing determined the position of a leak to within an accuracy of 5%, even when the location of the reflection from a leak is itself dispersed over a certain distance and, therefore, does not cause an exact reflection of the wave

Combined Experimental and Flexible Multibody Dynamic Investigation of High Energy Impact Induced Driveline Vibration

Lightly damped non-linear dynamic driveline components are subjected to excitation with rapid application of clutch and/or throttle. Modern thin-walled driveshaft tubes respond with a plethora of structural-acoustic modes under such impulsive conditions, which are onomatopoeically referred to as clonk in the vehicle industry. The underlying mechanisms for the occurrence of this phenomenon are investigated, using combined experimentation and flexible multi-body dynamics under impulsive impact conditions. The coincidence of high-frequency structural modes, coupled with acoustic response is highlighted for the broad-band spectral response of the hollow driveshaft tubes. The cyclic relationship of clonk with the shuffle response of the driveline system is also established for transient decay of the clonk phenomenon. In particular, the multi-body model is used to ascertain the effect of vehicle laden state on the propensity of driveline clonk, an approach not hitherto reported in literature

Fabrication and mechanical testing of a new sandwich structure with carbon fiber network core

The aim is the fabrication and mechanical testing of sandwich structures including a new core material known as fiber network sandwich materials. As fabrication norms for such a material do not exist as such, so the primary goal is to reproduce successfully fiber network sandwich specimens. Enhanced vibration testing diagnoses the quality of the fabrication process. These sandwich materials possess low structural strength as proved by the static tests (compression, bending), but the vibration test results give high damping values, making the material suitable for vibro-acoustic applications where structural strength is of secondary importance e.g., internal panelling of a helicopter

Keeping patients with epilepsy safe: a surmountable challenge?

This quality improvement project was inspired as an answer to a problem that intellectual disability teams have been struggling to manage whilst caring for people with epilepsy (PWE). The issue was that despite guidance to discuss the possibility of sudden unexpected death in epilepsy (SUDEP) be discussed with a newly diagnosed PWE this is rarely done. Additionally when, how, and what to discuss about SUDEP and reduce its risk is arbitrary, non-person centred, and with no structured evidence. Prior to initiating changes a discussion of SUDEP was recorded in just 10% of PWE. We introduced a check-list to help identify risk factors for SUDEP. We then modified the check-list, and then used it via telehealth, a way of contacting patients and their carers over the phone using the check-list approach. Following interventions, discussions of SUDEP are now recorded in 80% of PWE. Feedback from patients, carers and primary and secondary care professionals has been positive. We are now developing an app so that patients and carers can monitor their own risk factors, thus empowering them and increasing their knowledge and awareness of SUDEP

The effect of neuromuscular electrical stimulation on congenital talipes equinovarus following correction with the Ponseti method: a pilot study.

The Ponseti method for clubfoot treatment offers satisfactory initial correction, but success correlates with abduction brace compliance, which is variable. Electrical stimulation as a dynamic intervention to prevent relapses was investigated. Data were compared to a control group. There was a significant improvement in ankle range of motion only in the study group after short-term intervention, and a trend toward greater increase in calf circumference in this group. Parental perception was positive with no compliance issues. This study suggests stimulation is feasible with potential to increase ankle range of motion and facilitate muscle activity. It could be an important adjunct in preventing relapses, however, further studies with larger groups and longer intervention and follow-up duration are necessary

On the bistable zone of milling processes

A modal-based model of milling machine tools subjected to time-periodic nonlinear cutting forces is introduced. The model describes the phenomenon of bistability for certain cutting parameters. In engineering, these parameter domains are referred to as unsafe zones, where steady-state milling may switch to chatter for certain perturbations. In mathematical terms, these are the parameter domains where the periodic solution of the corresponding nonlinear, time-periodic delay differential equation is linearly stable, but its domain of attraction is limited due to the existence of an unstable quasi-periodic solution emerging from a secondary Hopf bifurcation. A semi-numerical method is presented to identify the borders of these bistable zones by tracking the motion of the milling tool edges as they might leave the surface of the workpiece during the cutting operation. This requires the tracking of unstable quasi-periodic solutions and the checking of their grazing to a time-periodic switching surface in the infinite-dimensional phase space. As the parameters of the linear structural behaviour of the tool/machine tool system can be obtained by means of standard modal testing, the developed numerical algorithm provides efficient support for the design of milling processes with quick estimates of those parameter domains where chatter can still appear in spite of setting the parameters into linearly stable domains

A Computer Vision-Based Approach for Non-contact Modal Analysis and Finite Element Model Updating

Computer vision-based techniques for modal analysis and system identification are rapidly becoming of great interest for both academic research and engineering practice in structural engineering. For instance, this is particularly relevant in fields such as bridge or tall building monitoring, where the large size of the structure would require an expensive sensor network, and for the characterisation of very slender, highly-flexible structural components, where physically-attached sensors cannot be deployed without altering the mass and stiffness of the system under investigation. This study concerns the latter case. Here, an algorithm for the full-field, non-contact extraction and processing of useful information from vibrational data is applied. Firstly, video acquisition is used to capture rapidly very spatially- and temporally-dense information regarding the vibrational behaviour of a high-aspect-ratio (HAR) prototype wing, with high image quality and high frame rate. Video processing is then applied to extract displacement time histories from the collected data; in turn, these are used to perform Modal Analysis (MA) and Finite Element Model Updating (FEMU). Results are benchmarked against the ones obtained from a single-point laser Doppler vibrometer (LDV). The study is performed on the beam-like spar of the wing prototype with and without the sensors attached to appreciate the disruptive effects of sensor loading. Promising results were achieved