The passive biomechanics of human pelvic collecting lymphatic vessels

The lymphatic system has a major significance in the metastatic pathways in women’s cancers. Lymphatic pumping depends on both extrinsic and intrinsic mechanisms, and the mechanical behavior of lymphatic vessels regulates the function of the system. However, data on the mechanical properties and function of human lymphatics are lacking. Our aim is to characterize, for the first time, the passive biomechanical behavior of human collecting lymphatic vessels removed at pelvic lymph node dissection during primary debulking surgeries for epithelial ovarian cancer. Isolated vessels were cannulated and then pressurized at varying levels of applied axial stretch in a calcium-free Krebs buffer. Pressurized vessels were then imaged using multi-photon microscopy for collagen-elastin structural composition and fiber orientation. Both pressure-diameter and force-elongation responses were highly nonlinear, and axial stretching of the vessel served to decrease diameter at constant pressure. Pressure-diameter behavior for the human vessels is very similar to data from rat mesenteric vessels, though the human vessels were approximately 10× larger than those from rats. Multiphoton microscopy revealed the vessels to be composed of an inner layer of elastin with an outer layer of aligned collagen fibers. This is the first study that successfully described the passive biomechanical response and composition of human lymphatic vessels in patients with ovarian cancer. Future work should expand on this knowledge base with investigations of vessels from other anatomical locations, contractile behavior, and the implications on metastatic cell transport

From hands to minds: Gestures promote understanding

Gestures serve many roles in communication, learning and understanding both for those who view them and those who create them. Gestures are especially effective when they bear resemblance to the thought they represent, an advantage they have over words. Here, we examine the role of conceptually congruent gestures in deepening understanding of dynamic systems. Understanding the structure of dynamic systems is relatively easy, but understanding the actions of dynamic systems can be challenging. We found that seeing gestures representing actions enhanced understanding of the dynamics of a complex system as revealed in invented language, gestures and visual explanations. Gestures can map many meanings more directly than language, representing many concepts congruently. Designing and using gestures congruent with meaning can augment comprehension and learning

Adaptive mechanisms of plants against salt stress and salt shock

Salinization process occurs when soil is contaminated with salt, which consequently influences plant growth and development leading to reduction in yield of many food crops. Responding to a higher salt concentration than the normal range can result in plant developing complex physiological traits and activation of stress-related genes and metabolic pathways. Many studies have been carried out by different research groups to understand adaptive mechanism in many plant species towards salinity stress. However, different methods of sodium chloride (NaCl) applications definitely give different responses and adaptive mechanisms towards the increase in salinity. Gradual increase in NaCl application causes the plant to have salt stress or osmotic stress, while single step and high concentration of NaCl may result in salt shock or osmotic shock. Osmotic shock can cause cell plasmolysis and leakage of osmolytes in plant. Also, the gene expression pattern is influenced by the type of methods used in increasing the salinity. Therefore, this chapter discusses the adaptive mechanism in plant responding to both types of salinity increment, which include the morphological changes of plant roots and aerial parts, involvement of signalling molecules in stress perception and regulatory networks and production of osmolyte and osmoprotective proteins

Investigation of wall shear stress related factors in realistic carotid bifurcation geometries and different flow conditions

Cardiovascular diseases are one of the major causes of death in the world; atherosclerosis being one aspect. Carotid bifurcation is one of the sites that are vulnerable to this disease. Wall Shear Stress (WSS) is known to be responsible for the process of atherogenesis. In this study, we have simulated the blood flow for Newtonian and non-Newtonian, steady and unsteady, flow conditions in three idealistic and five realistic geometries. A risk factor has been presented based on the results of wall shear stress and, then, a relation was found between geometrical features and the wall shear stress risk factor. Our main conclusions are: 1) The non-Newtonian behavior of blood elevates the value of wall shear stress, however, the wall shear stress pattern is similar, 2) The bifurcation angle is not the main cause of atherosclerosis and cannot be considered a predictor for atherosclerosis disease, and 3) The ratio of sinus diameter to the internal carotid artery diameter is more important than other geometrical factors, and the WSS pattern is influenced by this factor. © Sharif University of Technology, October 2010

Violation and lack of awareness of employment rights in the United Kingdom's hotel industry: Isolation, fragmentation and barriers to labour enforcement

The article examines the extent of labour violation in the UK hotel industry and identifies the challenges and difficulties that workers face to defend their employment rights. Drawing on interview material and documents, the article identifies the factors that weaken workers' capacities to bring forward complaints and discusses the organisational, institutional and individual factors making silence dominant in the sector. This multifaceted analysis demonstrates different layers of vulnerability that create a very unfavourable environment for the promotion of employment rights in a context of heightened levels of fear. We contribute to the existing studies by demonstrating that for precarious and insecure workers in particular, the UK model of individual employment rights has ‘no substance’. Our findings highlight that it jeopardises not only the enforcement of rights but also workers' ability to acquire comprehensive knowledge and awareness of them

A happy experience of a dark place: Consuming and performing the Jallianwala Bagh

This article adopts a phenomenological, ethnographic approach to examine place consumption and place experience through visitors' practices in situ. It focuses particularly on an examination of the embodied practices and performances of both tourists and the local community. Viewing memorial places as ‘performative fields’, we argue that a set of processes are simultaneously at play: while consuming the place and its representations (place consumption), visitors are also producing the meaning of the place through their embodied practices (place production) and, simultaneously, form and project a construct of their own selves (self-identity construction), within wider social narratives (social/national-identity construction). The simultaneity of these processes is empirically illustrated and supported by the findings from the qualitative research in the Jallianwala Bagh Memorial in Amritsar, India, where British colonial forces massacred more than one thousand peaceful protesters in 1919