The application of surface diathermy to the sclera, followed by ophthalmoscopic observation of the choroido-retinal reaction, is a time-honoured technique which may be used with shallow detachments; it fails with deep detachments, as no reaction can then be seen with the ophthalmoscope. Stallard (1958) advocated the focusing of a narrow beam of light from an ophthalmoscope on to the retinal hol...

Looping is a crucial early phase during heart development, as the initially straight heart tube (HT) deforms into a curved tube to lay out the basic plan of the mature heart. This paper focuses on the first phase of looping, called c-looping, when the HT bends ventrally and twists dextrally (rightward) to create a c-shaped tube. Previous research has shown that bending is an intrinsic process, ...

We consider the effects of going beyond the approximation of a straight string in mesons by using a flexible flux tube model wherein a Nambu-Goto string bends in response to quark accelerations. The curved string is dynamically identical to the straight string even for ultra-relativistic mesons except for a small additional radial momentum. We numerically solve the curved string model in the ca...

Ultrasound particle image velocimetry (PIV) can be used to obtain velocity fields in non-transparent geometries and/or fluids. In the current study, we use this technique to document the flow in a curved tube, using ultrasound contrast bubbles as flow tracer particles. The performance of the technique is first tested in a straight tube, with both steady laminar and pulsatile flows. Both experim...

Curved tubes of non-circular cross section are widely used in various fields technology. The change the planned operating modes technological processes is associated with wear executing mechanisms, which caused by unstable frequencies and amplitudes oscillations. Thus, issue determining oscillation parameters these elements becomes more significant. technique results tests for stresses, displac...

The evacuated tube solar collector ETC is studied intensively and extensively by experimental andtheoretical works, in order to investigate its performance enhancement of heat transfer, for Baghdad climatefrom April 2011 till the end March 2012. Experimental work carried out on a well instrumented collectorconsists 16 tubes aspect ratio 38.6 thermally insulated tank volume 112L. relationbetween...

Concentric tube continuum devices, known as active cannulas, consist of multiple pre-curved elastic tubes that extend telescopically and rotate axially with respect to each other. Through these degrees of freedom, an active cannula presents a dexterous and versatile “tentacle-like” mechanism for accessing targets in minimally invasive surgery. Deploying an active cannula in a practical surgical...

FtsZ assembles in vitro into protofilaments that can adopt two conformations-the straight conformation, which can assemble further into two-dimensional protofilament sheets, and the curved conformation, which forms minirings about 23 nm in diameter. Here, we describe the structure of FtsZ tubes, which are a variation of the curved conformation. In the tube the curved protofilament forms a shall...