A method for monitoring uterine activity in induced labour

A system for the quantitative assessment of uterine activity during an oxytocin-induced labour has been developed. This has been achieved using relatively simple analogue techniques and can easily be used in the labour ward alongside existing monitoring equipment. Initial results indicate that a plateau of uterine activity can be easily recognised from the display and maintained at oxytocin dosage levels below those that might normally be used.     

On‐off iterative adaptive controller for low‐power micro‐robotic step regulation

A novel model‐free iterative adaptive controller is presented for low‐power control of piezoelectric actuators. The controller uses simple adaptation rules based on known general behavior of piezoelectric actuators to adjust on‐off switching times to drive piezoelectric actuators through a desired transient step motion. Adaptation rules are based on small numbers of measurements taken during each iteration of the actuator movement. Combined with the use of only on‐off control inputs, controller implementation can be possible at much lower overall power levels than would be needed to implement a conventional control strategy such as through pulse‐width‐modulation (PWM) with real‐time feedback. Such power savings are particularly important for the intended controller application to piezoelectric microactuators driving autonomous terrestrial micro‐robots. A method for predicting convergence of systems with nominally linear dynamics and unknown, bounded nonlinearities is described, and applied to a sample target piezoelectric actuator. The controller is tested in simulation and experimentally on a piezoelectric cantilever actuator, and shows predicted convergence to the desired response. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

The diffusion of ion-implanted arsenic in thermally grown SiO2

The diffusivity of ion-implanted As in SiO₂ is investigated as a function of the implanted dose, oxide type and ambient in the 1000–1200° C temperature range. The As diffusivity in oxide is extracted, using electrical methods, from the profiles of As diffused into the substrate. Secondary-ion-mass-spectroscopy depth profiles of some of the samples are in agreement with the results of the electrical methods. Two types of oxide are investigated: Dry oxide grown in O₂ and wet oxide grown in steam. The diffusivity is characterized as a function of the temperature for dry oxide annealed in N₂, and for wet oxide annealed both in N₂ and in N₂/H₂ (10%). The measured As diffusivity vs temperature is fitted to a single activation energy exponential model. For the wet-grown oxide, the extracted activation energy for the N₂/H₂ (10%) annealed sample is 4.4 ± 0.5 eV and for the N₂ annealed oxide it is found to be 5.5 ± 0.5 eV. For oxide grown in dry oxygen the As diffusivity is characterized also as a function of the implant dose. It is found to be independent of the implanted dose, for ion energy of 40 keV and dose in the 10¹²–10¹⁵ cm^-2 range, and its activation energy equals 4.7 ± 0.5 eV. The extracted parameters were installed in the SUPREM-III process simulation program and correctly predict ion-implanted As diffusion behavior in SiO₂.     

A gene for autosomal recessive symmetrical spastic cerebral palsy maps to chromosome 2q24-25

Cerebral palsy has an incidence of approximately 1/500 births, although this varies between different ethnic groups. Genetic forms of the disease account for approximately 1%-2% of cases in most countries but contribute a larger proportion in populations with extensive inbreeding. We have clinically characterized consanguineous families with multiple children affected by symmetrical spastic cerebral palsy, to locate recessive genes responsible for this condition. The eight families studied were identified from databases of patients in different regions of the United Kingdom. After ascertainment and clinical assessment, we performed a genomewide search for linkage, using 290 polymorphic DNA markers. In three families, a region of homozygosity at chromosome 2q24-q25 was identified between the markers D2S124 and D2S148. The largest family gave a maximum LOD score of 3.0, by multipoint analysis (HOMOZ). The maximum combined multipoint LOD score for the three families was 5.75. The minimum region of homozygosity is approximately 5 cM between the markers D2S124 and D2S2284. We have shown that a proportion of autosomal recessive symmetrical spastic cerebral palsy maps to chromosome 2q24-25. The identification of genes involved in the etiology of cerebral palsy may lead to improved management of this clinically intractable condition.