Preliminary assessment of the SensiumVitals®: A low-cost wireless solution for patient surveillance in the general wards.

This paper presents SensiumVitals(®) - an FDA cleared and CE marked wireless wearable vital signs monitoring system, developed for frequent surveillance of in-hospital patients. A number of in-house evaluations with artificial data and healthy volunteers were carried out in different stages to assess the reliability of two crucial vital signs measured by the system - respiration and heart rate. In order to illustrate the potential of the system in hospital, a subset of data collected from acutely-ill patients during a separate clinical trial was also analyzed. In all cases the results revealed satisfactory agreement between the values reported by SensiumVitals(®) and those recorded simultaneously by a clinically-approved bedside monitor. However, further work will be required to improve the reliability of the system under certain clinical conditions; which, although not crucial for our intended population (i.e. patients in general ward), pose interesting challenges for upgrading our technology for future use in these types of patients.

The acute toxicity of fipronil to two non-target invertebrates associated with mosquito breeding sites in Australia.

Mosquito-borne arboviruses are a significant health issue in the irrigation areas of south-eastern Australia. Fipronil, a pyrazole insecticide with strong activity against larval Culex species, was tested for its acute effects on Simocephalus elizabethae (Daphniidae) and Polypedilum nubiferum (Chironomidae), two non-target invertebrates associated with Australian rice field mosquito habitats. Technical and formulated fipronil were assessed in the presence or absence of particulate artificial diets in 48 h static bioassays. LC(50) values for neonate S. elizabethae ranged from 11.13 to 19.12 µgl(-1) whilst those for final instar P. nubiferum ranged from 0.89 to 2.18 µgl(-1). Feeding during exposure significantly reduced the susceptibility of P. nubiferum to both technical and formulated fipronil. The effect of feeding was less consistent in Simocephalus bioassays, where much less food was present. We investigated whether adsorption to unconsumed food particles may have limited fipronil bioavailability by using solid-phase microextraction and gas chromatography to measure the available fipronil from fed and unfed systems 24h after establishment. Differences between the systems were not significant (P>0.05). The significantly higher LC(50) values in the fed Polypedilum bioassays do not appear to be a consequence of reduced fipronil bioavailability. Observed differences in toxicity probably reflect increased stresses associated with food deprivation in the unfed bioassays. Our results support published data on the toxicity of fipronil to aquatic invertebrates which suggest that the use of this material as a mosquito larvicide may cause disruption to aquatic ecosystems.

Sensium: an ultra-low-power wireless body sensor network platform: design & application challenges.

In this paper we present a system-on-chip for wireless body sensor networks, which integrates a transceiver, hardware MAC protocol, microprocessor, IO peripherals, memories, ADC and custom sensor interfaces. Addressing the challenges in the design, this paper will continue to discuss the issues in the applications of this technology to body worn monitoring for real-time measurement of ECG, heart rate, physical activity, respiration and/or skin temperature. Two application challenges are described; the real-time measurement of energy expenditure using the LifePebble, and; the development issues surrounding the 'Digital Patch'.

Energy efficient medium access protocol for wireless medical body area sensor networks.

This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-slave architecture, where the body-worn slave node periodically sends sensor readings to a central master node. Unlike traditional peer-to-peer wireless sensor networks, the nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor nodes are in standby or sleep mode until the centrally assigned time slot. Once a node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central node and is addressed uniquely to a slave node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more ldquoflexiblerdquo network MAC protocols such as 802.11 or Zigbee. As duty cycle is reduced, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13- mum CMOS process.

Laboratory and field studies on the effect of molinate, clomazone, and thiobencarb on nontarget aquatic invertebrates.

The midge Chironomus tepperi was used in laboratory experiments to assess the relative toxicity of formulated molinate, clomazone, and thiobencarb, three herbicides used in Australian rice crops. Static bioassays were initiated with first-instar larvae at herbicide concentrations between 0.0625 and 2 times the anticipated field concentrations (AFCs) expected from the registered application rates. Adult emergence success, development time, and wing length were used as indices of the effect of each herbicide. Clomazone had no effect on any parameters at concentrations up to 0.288 mg/L (p > 0.05). Molinate significantly increased development time at concentrations equivalent to the AFC (3.6 mg/L) and above (p < 0.05). Thiobencarb reduced emergence success of adult C. tepperi at 0.0625 times the AFC (0.1875 mg/L) as well as decreasing male adult size and increasing development time for males and females at 0.125 times the AFC (p < 0.05). Nontarget effects of the herbicides on aquatic invertebrate communities were assessed in shallow experimental ponds using commercial application rates. One week after treatment, only thiobencarb had a significant effect, suppressing populations of chironomids, calanoids, and cyclopoids (p < 0.05). Four weeks later, all populations had recovered, equaling or exceeding control densities.

Ethylene synthesis in lettuce seeds: its physiological significance.

The germination and pregermination ethylene production of Grand Rapids lettuce seeds (Lactuca sativa L.) incubated at 20 C after a red light treatment are inhibited if the seeds are first imbibed at 30 C for 36 hours. In this study, low concentrations of ethylene were found to enhance the germination of seeds pretreated at 30 C more than that of untreated controls. In the presence of high concentrations of ethylene, pretreated seeds and controls germinated at a similar rate. These results are consistent with the view that a prolonged imbibition at 30 C inhibits germination at a lower temperature through its effect on the ethylene production of the seeds. As a further test of the hypothesis, estimates were made of the pregermination ethylene content of untreated seeds and pretreated seeds incubated in the presence of sufficient ethylene to make them germinate as rapidly as untreated seeds. The values obtained were 0.65 and 0.74 nanoliter of ethylene per gram (dry weight) of seeds, respectively.

Antagonistic effects of high and low temperature pretreatments on the germination and pregermination ethylene synthesis of lettuce seeds.

Red light-induced germination of Grand Rapids lettuce seeds (Lactuca sativa L.) incubated at 20 C was inhibited if the seeds were first imbibed at 30 C for 36 hours. This effect was counteracted by exogenous ethylene and associated with a reduction in the rate at which the seeds produced ethylene throughout the pregermination period. A chilling treatment reversed the effect of a prior imbibition at 30 C on both germination and ethylene production. The possibility that the pretreatments influence germination through their effects on ethylene production is discussed.Other evidence presented indicates that the inability of seeds to germinate at supraoptimal temperature is not due either to a rapid loss of far red-absorbing phytochrome or to an inadequate capacity for ethylene synthesis. It was also shown that a chilling treatment potentiated germination at high temperature without affecting the ethylene synthetic capacity of the seeds.

Two effects of prolonged far red light on the response of lettuce seeds to exogenous gibberellin.

Prolonged far red irradiation of imbibed lettuce seeds (Lactuca sativa L. cv. Grand Rapids) makes them unresponsive to subsequent treatment with gibberellin. It has been found that this effect is overcome by supplying gibberellin buffered at a low pH. On the basis of this and other evidence it is suggested that an extended far-red exposure causes a loss of gibberellin sensitivity through an effect on the permeability of the endosperm. In seeds treated simultaneously with gibberellin and far red light, the hormone is taken up at the beginning of the irradiation, but its action is suspended until the seeds are placed in the dark.

The effects of kinetin and contaminating bacteria on the incorporation of (32)P-orthophosphate into various fractions of nucleic acid extracted from radish leaves.

By comparing (32)P-orthophosphate incorporation into nucleic acid extracts of sterile and non-sterile radish leaf discs, it was shown that contaminating bacteria cause a 2-4 fold increase in the rate of precursor incorporation and alter the pattern of label distribution after fractionation of the extracts by sedimentation through sucrose gradients or chromatography on MAK(1) columns. Using sterile senescing radish leaf discs, a stimulation of (32)P-orthophosphate incorporation into various fractions of nucleic acid was observed as a result of kinetin treatment.

The effect of kinetin on the incorporation of labelled orotate into various fractions of ribonucleic acid of excised radish leaf discs.

Discs from senescing radish leaves were floated either on water or on a solution of kinetin and incubated in the dark. The kinetin-treated discs were fed with orotic acid-5-T and the control discs with orotic acid-6-C(14). The two lots of discs were combined and the RNA extracted by the phenol method. The H(3):C(14) ratio of the RNA after fractionation on sucrose density gradient was compared with the H(3):C(14) ratio of RNA extracted from two lots of control discs, one fed with orotic acid-5-T and the other with orotic acid-6-C(14) and then extracted together. In this way it was found that 21 hours treatment with kinetin causes a small but consistent stimulation of labelled precursor incorporation into all classes of RNA investigated.