799 research outputs found
Apparatus to control and visualize the impact of a high-energy laser pulse on a liquid target
We present an experimental apparatus to control and visualize the response of
a liquid target to a laser-induced vaporization. We use a millimeter-sized drop
as target and present two liquid-dye solutions that allow a variation of the
absorption coefficient of the laser light in the drop by seven orders of
magnitude. The excitation source is a Q-switched Nd:YAG laser at its
frequency-doubled wavelength emitting nanosecond pulses with energy densities
above the local vaporization threshold. The absorption of the laser energy
leads to a large-scale liquid motion at timescales that are separated by
several orders of magnitude, which we spatiotemporally resolve by a combination
of ultra-high-speed and stroboscopic high-resolution imaging in two orthogonal
views. Surprisingly, the large-scale liquid motion at upon laser impact is
completely controlled by the spatial energy distribution obtained by a precise
beam-shaping technique. The apparatus demonstrates the potential for accurate
and quantitative studies of laser-matter interactions.Comment: Submitted to Review of Scientific Instrument
Association of ABCB1, 5-HT3B receptor and CYP2D6 genetic polymorphisms with ondansetron and metoclopramide antiemetic response in Indonesian cancer patients treated with highly emetogenic chemotherapy.
Our study shows that in Indonesian cancer patients treated with highly cytostatic emetogenic, carriership of the CTG haplotype of the ABCB1 gene is related to an increased risk of delayed chemotherapy-induced nausea and vomiting
COVID-19 vaccine roll-out in South Africa: The added value of wastewater surveillance for SARS-CoV-2
INFECTION OF THE HUMAN MONOCYTIC CELL-LINE MONO MAC6 WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 AND TYPE-2 RESULTS IN LONG-TERM PRODUCTION OF VIRUS VARIANTS WITH INCREASED CYTOPATHOGENICITY FOR CD4+ T-CELLS
Dimethylarginine Dimethylaminohydrolase-1 Transgenic Mice Are Not Protected from Ischemic Stroke
Methylated arginines are endogenous analogues of L-arginine, the substrate for nitric oxide (NO) synthase. Asymmetric dimethylarginine (ADMA) interferes with NO formation, causing endothelial dysfunction. ADMA is a predictor of cardiovascular events and mortality in humans. It is eliminated primarily by enzymatic activity of dimethylarginine dimethylaminohydrolase (DDAH).We investigated whether human DDAH-1 (hDDAH-1) transgenicity protects from ischemic tissue damage in temporary middle cerebral artery occlusion (tMCAO) in mice. Infarct sizes did not significantly differ between hDDAH-1 transgenic (TG) mice and wild-type littermates (WT). As expected, ADMA plasma concentrations were significantly decreased, cerebral hDDAH expression and protein significantly increased in transgenic animals. Interestingly, neither brain tissue DDAH activity nor ADMA concentrations were different between TG and WT mice. In contrast, muscular DDAH activity was generally lower than in brain but significantly increased in TG mice.Our study demonstrates that hDDAH-1 transgenic mice are not protected from ischemic cerebral tissue damage in tMCAO. This lack of protection is due to high basal cerebral DDAH activity, which is not further increasable by transgenic overexpression of DDAH
Which activities threaten independent living of elderly when becoming problematic : inspiration for meaningful service robot functionality
Purpose: In light of the increasing elderly population and the growing demand for home care, the potential of robot support is given increasing attention. In this paper, an inventory of activities was made that threaten independent living of elderly when becoming problematic. Results will guide the further development of an existing service robot, the Care-O-bot®. Method: A systematic literature search of PubMed was performed, focused on the risk factors for institutionalization. Additionally, focus group sessions were conducted in the Netherlands, United Kingdom and France. In these focus group sessions, problematic activities threatening the independence of elderly people were discussed. Three separate target groups were included in the focus group sessions: (1) elderly persons (n = 41), (2) formal caregivers (n = 40) and (3) informal caregivers (n = 32). Results: Activities within the International Classification of Functioning domains mobility, self-care, and interpersonal interaction and relationships were found to be the most problematic. Conclusions: A distinct set of daily activities was identified that may threaten independent living, but no single activity could be selected as the main activity causing a loss of independence as it is often a combination of problematic activities that is person-specific. Supporting the problematic activities need not involve a robotic solution Read More: http://informahealthcare.com/doi/abs/10.3109/17483107.2013.840861Peer reviewe
Analytical and experimental characterization of a miniature calorimetric sensor in pulsatile flow
The behaviour of a miniature calorimetric sensor, which is under
consideration for catheter-based coronary artery flow assessment, is
investigated in both steady and pulsatile tube flow. The sensor is composed of
a heating element operated at constant power, and two thermopiles that measure
flow-induced temperature differences over the sensor surface.
An analytical sensor model is developed, which includes axial heat conduction
in the fluid and a simple representation of the solid wall, assuming a
quasi-steady sensor response to the pulsatile flow. To reduce the mathematical
problem, described by a two-dimensional advection-diffusion equation, a
spectral method is applied. A Fourier transform is then used to solve the
resulting set of ordinary differential equations and an analytical expression
for the fluid temperature is found. To validate the analytical model,
experiments with the sensor mounted in a tube have been performed in steady and
pulsatile water flow with various amplitudes and Strouhal numbers. Experimental
results are generally in good agreement with theory and show a quasi-steady
sensor response in the coronary flow regime. The model can therefore be used to
optimize the sensor design for coronary flow assessment
Assistive technology design and development for acceptable robotics companions for ageing years.
A new stream of research and development responds to changes in life expectancy across the world. It includes technologies which enhance well-being of individuals, specifically for older people. The ACCOMPANY project focuses on home companion technologies and issues surrounding technology development for assistive purposes. The project responds to some overlooked aspects of technology design, divided into multiple areas such as empathic and social human-robot interaction, robot learning and memory visualisation, and monitoring persons’ activities at home. To bring these aspects together, a dedicated task is identified to ensure technological integration of these multiple approaches on an existing robotic platform, Care-O-Bot®3 in the context of a smart-home environment utilising a multitude of sensor arrays. Formative and summative evaluation cycles are then used to assess the emerging prototype towards identifying acceptable behaviours and roles for the robot, for example role as a butler or a trainer, while also comparing user requirements to achieved progress. In a novel approach, the project considers ethical concerns and by highlighting principles such as autonomy, independence, enablement, safety and privacy, it embarks on providing a discussion medium where user views on these principles and the existing tension between some of these principles, for example tension between privacy and autonomy over safety, can be captured and considered in design cycles and throughout project developments
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