Optimization of Cricket-inspired, Biomimetic Artificial Hair Sensors for Flow Sensing

High density arrays of artificial hair sensors, biomimicking the extremely sensitive mechanoreceptive filiform hairs found on cerci of crickets have been fabricated successfully. We assess the sensitivity of these artificial sensors and present a scheme for further optimization addressing the deteriorating effects of stress in the structures. We show that, by removing a portion of chromium electrodes close to the torsional beams, the upward lift at the edges of the membrane due to the stress, will decrease hence increase the sensitivity.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Biomimetic flow-sensor arrays based on the filiform hairs on the cerci of crickets

In this paper we report on the latest developments in biomimetic flow-sensors based on the flow sensitive mechano-sensors of crickets. Crickets have one form of acoustic sensing evolved in the form of mechanoreceptive sensory hairs. These filiform hairs are highly perceptive to low-frequency sound with energy sensitivities close to thermal threshold. Arrays of artificial hair sensors have been fabricated using a surface micromachining technology to form suspended silicon nitride membranes and double-layer SU-8 processing to form 1 mm long hairs. Previously, we have shown that these hairs are sensitive to low-frequency sound, using a laser vibrometer setup to detect the movements of the nitride membranes. We have now realized readout electronics to detect the movements capacitively, using electrodes integrated on the membranes

Optimization Of Bio-inspired Hair Sensor Arrays

Crickets use a pair of hairy appendages on their abdomen called cerci, each of which contains numerous mechano-receptive filiform hairs. These sensitive hairs can respond even to the slightest air movements, down to 0.03 mm/s, generated by the approaching predators and initiating an escape mechanism in the crickets. Bio-mimicking the cricket cerci, arrays of artificial hair sensors have been successfully fabricated using advanced MEMS techniques. Despite its appreciable performance, the actual cricket filiform hairs outperform artificial hair sensors by several orders in sensitivity. Nevertheless, more careful look at the anatomy and physiology of the cricket cerci provides new directions to be explored with MEMS technologies to realize higher sensitivities on a par with crickets’. This paper aims to provide an overview of comparisons between the actual and artificial hair sensors in terms of sensitivity, structural functionalities and robustness and draws out constructive insights to optimize sensor performance

Fabrication scheme for dense aquatic flow sensor arrays

A fabrication scheme to realize dense arrays of flexible, closed membranes with a small gap separating them from the substrate is presented. These membranes are the first step towards aquatic hair based flow sensors biomimicking fish lateral line. Electrodes are integrated underneath the membrane to avoid contact with the liquid. Arrays of membranes with a diameter of 100 μm, gap height of 3 μm, and mutual distance of 200 μm have been successfully fabricated

Malignant mixed mullerian tumor of the uterus associated with tamoxifen therapy in a patient with a history of breast cancer

Tamoxifen is the drug of choice in the treatment of breast cancer. Recent reports show an increased incidence of endometrial carcinoma in patients taking tamoxifen. In this article, we report a case of malignant mixed mullerian tumor after tamoxifen use. Copyright © 2006 by Razi Institute for Drug Research (RIDR)

Water and livelihoods : a participatory analysis of a Mexican rural community

Accompanying material includes video and computer disc, see Library catalogue record.Over 70% of Mexican farms produce only for self-subsistence and lack the necessary economies of scale to be commercial. In the arid and semi-arid regions of the country, which represents 52% of Mexico’s total land, farming is difficult and poverty is common. These zones are distinguished by a low level of public investment, scarce official support, lack of inter-institutional coordination and non-existence of an integrated policy for development. Whether development has occurred as a result of the diverse range of projects and programmes is uncertain. This uncertainty is in part due to the variation in definitions, paradigms and goals of development. The concept of development has evolved from rapid economic growth to a more holistic view which encompasses eradication of poverty and fostering of sustainability, participation and empowerment. Using participatory research, the case study evaluated the effect of the project ‘Water and Life’ on the development of the rural community of San Felipe (situated in the semi-arid region of Mexico). The research sought to determine whether the community of San Felipe is sustainable by exploring the processes by which people achieve (or fail to achieve) sustainable livelihoods. Also the research evaluated whether the project ‘Water and Life’ assisted in the process of achieving sustainable livelihoods in San Felipe. Lessons learnt for future development endeavours are derived from the study. Through the use of PRA techniques, research revealed that the community of San Felipe is very vulnerable and cannot secure enough food for its inhabitants. The project ‘Water and Life’ has brought about positive changes to the community, one of its major achievements has been to provide the community with three rainwater harvesting systems with a storage capacity of approximately 1.2 million L. However, the project has only partially satisfied the needs of the community and the project has not reduced the vulnerability of the community markedly. Moreover, food security is still an unattainable goal for the community and the benefits of the project are likely to disappear in 25 or 30 years. Research identified opportunities for San Felipe to improve its livelihood sustainability by better management of its valuable natural resources. In addition, improved participation of women in decision-making, increased coordination of formal groups of the community and the training of women and youth could significantly reduce the vulnerability of San Felipe if addressed by the project ‘Water and Life’ and the community