Microfluidic technology in vascular research : the endothelial response to shear stress

Vascular endothelial cells form the inner lining of all blood vessels. These cells are highly responsive to the shear stress that is caused by blood flowing over their surface. In this thesis, several aspects of the endothelial response to shear stress are studied. The experiments focus on signal transduction, cytoskeletal remodeling, migration, micromechanical changes and uptake of low density lipoprotein. Most of these experiments were performed by using microfluidic set-ups. In these set-ups, cells are cultured and subjected to experimental conditions in micrometer-sized channels. Several advantages and challenges associated with applying this new technology in vascular research are discussed

Numerical investigation towards a HiTAC condition in a 9MW heavy fuel-oil boiler

In this study, several conditions in a 9 MW heavy fuel-oil boiler were numerically studied in order to get a better understanding of the application of HiTAC in such a boiler. Simulations were done with an Euler- Lagrange approach. The Eddy Dissipation model was used for combustion. Simulation results showed that by recycling various ratios of flue gas into the primary and secondary air, a more uniform temperature distribution can be achieved. Besides, thermal NOX can be reduced to a lower level. Radiation from soot has shown to have a considerable influence on the predicted temperature profiles. It can reduce the peak temperature by 140 K in the case with hot combustion air

Cancer and heart disease:associations and relations

Emerging evidence supports that cancer incidence is increased in patients with cardiovascular (CV) disease and heart failure (HF), and patients with HF frequently die from cancer. Recently, data have been generated showing that circulating factors in relation to HF promote tumour growth and development in murine models, providing proof that a causal relationship exists between both diseases. Several common pathophysiological mechanisms linking HF to cancer exist, and include inflammation, neuro-hormonal activation, oxidative stress and a dysfunctional immune system. These shared mechanisms, in combination with risk factors, in concert may explain why patients with HF are prone to develop cancer. Investigating the new insights linking HF with cancer is rapidly becoming an exciting new field of research, and we herein review the most recent data. Besides insights in mechanisms, we call for clinical awareness, that is essential to optimize treatment strategies of patients having developed cancer with a history of HF. Finally, ongoing and future trials should strive for comprehensive phenotyping of both CV and cancer end points, to allow optimal usefulness of data, and to better describe and understand common characteristics of these two lethal diseases

Iron deficiency in heart failure:Mechanisms and pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID

Vibration isolation with high thermal conductance for a cryogen-free dilution refrigerator

We present the design and implementation of a mechanical low-pass filter vibration isolation used to reduce the vibrational noise in a cryogen-free dilution refrigerator operated at 10 mK, intended for scanning probe techniques. We discuss the design guidelines necessary to meet the competing requirements of having a low mechanical stiffness in combination with a high thermal conductance. We demonstrate the effectiveness of our approach by measuring the vibrational noise levels of an ultrasoft mechanical resonator positioned above a SQUID. Starting from a cryostat base temperature of 8 mK, the vibration isolation can be cooled to 10.5 mK, with a cooling power of 113 $\mu$W at 100 mK. We use the low vibrations and low temperature to demonstrate an effective cantilever temperature of less than 20 mK. This results in a force sensitivity of less than 500 zN/$\sqrt{\mathrm{Hz}}$, and an integrated frequency noise as low as 0.4 mHz in a 1 Hz measurement bandwidth