Evaluation of sensor configurations for robotic surgical instruments

Designing surgical instruments for robotic-assisted minimally-invasive surgery (RAMIS) is challenging due to constraints on the number and type of sensors imposed by considerations such as space or the need for sterilization. A new method for evaluating the usability of virtual teleoperated surgical instruments based on virtual sensors is presented. This method uses virtual prototyping of the surgical instrument with a dual physical interaction, which allows testing of different sensor configurations in a real environment. Moreover, the proposed approach has been applied to the evaluation of prototypes of a two-finger grasper for lump detection by remote pinching. In this example, the usability of a set of five different sensor configurations, with a different number of force sensors, is evaluated in terms of quantitative and qualitative measures in clinical experiments with 23 volunteers. As a result, the smallest number of force sensors needed in the surgical instrument that ensures the usability of the device can be determined. The details of the experimental setup are also included.

SPARE-ICE: synergistic Ice Water Path from passive operational sensors

This article presents SPARE-ICE, the Synergistic Passive Atmospheric Retrieval Experiment-ICE. SPARE-ICE is the first Ice Water Path (IWP) product combining infrared and microwave radiances. By using only passive operational sensors, the SPARE-ICE retrieval can be used to process data from at least the NOAA 15 to 19 and MetOp satellites, obtaining time series from 1998 onward. The retrieval is developed using collocations between passive operational sensors (solar, terrestrial infrared, microwave), the CloudSat radar, and the CALIPSO lidar. The collocations form a retrieval database matching measurements from passive sensors against the existing active combined radar-lidar product 2C-ICE. With this retrieval database, we train a pair of artificial neural networks to detect clouds and retrieve IWP. When considering solar, terrestrial infrared, and microwave-based measurements, we show that any combination of two techniques performs better than either single-technique retrieval. We choose not to include solar reflectances in SPARE-ICE, because the improvement is small, and so that SPARE-ICE can be retrieved both daytime and nighttime. The median fractional error between SPARE-ICE and 2C-ICE is around a factor 2, a figure similar to the random error between 2C-ICE ice water content (IWC) and in situ measurements. A comparison of SPARE-ICE with Moderate Resolution Imaging Spectroradiometer (MODIS), Pathfinder Atmospheric Extended (PATMOS-X), and Microwave Surface and Precipitation Products System (MSPPS) indicates that SPARE-ICE appears to perform well even in difficult conditions. SPARE-ICE is available for public use.

Study on the application of cool paintings for the passive cooling of existing buildings in Mediterranean climates

Building roofs play a very important role in the energy balance of buildings, especially in summer, when they are hit by a rather high solar irradiance. Depending on the type of finishing layer, roofs can absorb a great amount of heat and reach quite high temperatures on their outermost surface, which determines significant room overheating. However, the use of highly reflective cool materials can help to maintain low outer surface temperatures; this practice may improve indoor thermal comfort and reduce the cooling energy need during the hot season.This technology is currently well known and widely used in the USA, while receiving increasing attention in Europe. In order to investigate the effectiveness of cool roofs as a passive strategy for passive cooling in moderately hot climates, this paper presents the numerical results of a case study based on the dynamic thermal analysis of an existing office building in Catania (southern Italy, Mediterranean area). The results show how the application of a cool paint on the roof can enhance the thermal comfort of the occupants by reducing the operative temperatures of the rooms and to reduce the overall energy needs of the building for space heating and cooling.

Cool roofs for passive cooling: performance in different climates and for different insulation levels in Italy

Roofs are severely hit by solar radiation in summer; hence the use of cool materials on the finishing layer provides a significant reduction in the heat flow entering the building, with sensible attenuation in the building cooling load. In this paper, a case study is presented, based on the dynamic simulation of an existing office building in Catania (southern Italy). Here, a part of the roof has been recently treated with a commercial cool paint, with the aim of improving thermal comfort in summer. Hence, the simulations represent a preliminary study that will allow assessing the expected effectiveness of the intervention. More in detail, the results of the simulations will be discussed in terms of both thermal comfort and energy savings, through the evaluation of parameters such as the roof surface temperature, the operative temperature and the cooling load for both conditions, i.e. with and without the cool paint. The paper also discusses the potential increase in the energy needs for winter heating, and looks at the overall annual balance in terms of primary energy; this is made by considering different climatic conditions and envelope characteristics. These aspects are usually not well highlighted in the current scientific literature.

Cross layer based protocols for energy aware and critical data delivery related applications using wireless sensor networks

Wireless Sensor Networks (WSNs) have been an exciting topic in recent years. The services offered by a WSN can be classified into three major categories: monitoring, alerting, and information on demand. WSNs have been used for a variety of applications related to the environment (agriculture, water and forest fire detection), the military, buildings, health (elderly people and home monitoring), disaster relief, and area or industrial monitoring. In most WSNs tasks like processing the sensed data, making decisions and generating emergency messages are carried out by a remote server, hence the need for efficient means of transferring data across the network. Because of the range of applications and types of WSN there is a need for different kinds of MAC and routing protocols in order to guarantee delivery of data from the source nodes to the server (or sink). In order to minimize energy consumption and increase performance in areas such as reliability of data delivery, extensive research has been conducted and documented in the literature on designing energy efficient protocols for each individual layer. The most common way to conserve energy in WSNs involves using the MAC layer to put the transceiver and the processor of the sensor node into a low power, sleep state when they are not being used. Hence the energy wasted due to collisions, overhearing and idle listening is reduced. As a result of this strategy for saving energy, the routing protocols need new solutions that take into account the sleep state of some nodes, and which also enable the lifetime of the entire network to be increased by distributing energy usage between nodes over time. This could mean that a combined MAC and routing protocol could significantly improve WSNs because the interaction between the MAC and network layers lets nodes be active at the same time in order to deal with data transmission. In the research presented in this thesis, a cross-layer protocol based on MAC and routing protocols was designed in order to improve the capability of WSNs for a range of different applications. Simulation results, based on a range of realistic scenarios, show that these new protocols improve WSNs by reducing their energy consumption as well as enabling them to support mobile nodes, where necessary. A number of conference and journal papers have been published to disseminate these results for a range of applications.

Mobile sink based fault diagnosis scheme for wireless sensor networks

Network diagnosis in Wireless Sensor Networks (WSNs) is a difficult task due to their improvisational nature, invisibility of internal running status, and particularly since the network structure can frequently change due to link failure. To solve this problem, we propose a Mobile Sink (MS) based distributed fault diagnosis algorithm for WSNs. An MS, or mobile fault detector is usually a mobile robot or vehicle equipped with a wireless transceiver that performs the task of a mobile base station while also diagnosing the hardware and software status of deployed network sensors. Our MS mobile fault detector moves through the network area polling each static sensor node to diagnose the hardware and software status of nearby sensor nodes using only single hop communication. Therefore, the fault detection accuracy and functionality of the network is significantly increased. In order to maintain an excellent Quality of Service (QoS), we employ an optimal fault diagnosis tour planning algorithm. In addition to saving energy and time, the tour planning algorithm excludes faulty sensor nodes from the next diagnosis tour. We demonstrate the effectiveness of the proposed algorithms through simulation and real life experimental results.

Passive Restoration in Biodiversity Hotspots: Consequences for an Atlantic Rainforest Lizard Taxocene

Long-term conservation in biodiversity hotspots depends on the recovery of communities in secondary forest fragments. In most cases, however, recovery strategies for these areas are based only on passive restoration. It is therefore necessary to determine the efficiency of such strategies. In this study, we assess the efficiency of passive restoration on a 567-ha 28-yr-old fragment of Atlantic Rainforest in Northeastern Brazil. We measured richness, composition, abundance and biomass of a lizard taxocene and also vegetation structure and availability of several microhabitat descriptors in 18 plots of this secondary forest. We then compared them with measures in 29 plots from two neighboring reference sites. Species richness, abundance, biomass and microhabitat descriptors availability inside the secondary fragment did not differ from reference sites. However, composition and vegetation structure showed small differences. Some forest specialist lizards, which should be a focus of conservation efforts in fragmented landscapes of the Atlantic Rainforest, were not found in the fragment and data indicate that this was not due to sampling or a lack of suitable habitat or microhabitat. In the presence of preserved source sites, passive restoration may be a cheap and effective way to recover lizard taxocenes of the Atlantic Rainforest. Some of the species may need to be re-introduced to accelerate the full recovery of original composition of lizard taxocenes in secondary Atlantic Rainforests.

Use of Information Visualization Methods Eliminating Cross Talk in Multiple Sensing Units Investigated for a Light-Addressable Potentiometric Sensor

The integration of nanostructured films containing biomolecules and silicon-based technologies is a promising direction for reaching miniaturized biosensors that exhibit high sensitivity and selectivity. A challenge, however, is to avoid cross talk among sensing units in an array with multiple sensors located on a small area. In this letter, we describe an array of 16 sensing units, of a light-addressable potentiometric sensor (LAPS), which was made with layer-by-Layer (LbL) films of a poly(amidomine) dendrimer (PAMAM) and single-walled carbon nanotubes (SWNTs), coated with a layer of the enzyme penicillinase. A visual inspection of the data from constant-current measurements with liquid samples containing distinct concentrations of penicillin, glucose, or a buffer indicated a possible cross talk between units that contained penicillinase and those that did not. With the use of multidimensional data projection techniques, normally employed in information Visualization methods, we managed to distinguish the results from the modified LAPS, even in cases where the units were adjacent to each other. Furthermore, the plots generated with the interactive document map (IDMAP) projection technique enabled the distinction of the different concentrations of penicillin, from 5 mmol L(-1) down to 0.5 mmol L(-1). Data visualization also confirmed the enhanced performance of the sensing units containing carbon nanotubes, consistent with the analysis of results for LAPS sensors. The use of visual analytics, as with projection methods, may be essential to handle a large amount of data generated in multiple sensor arrays to achieve high performance in miniaturized systems.

Late Quaternary sedimentation in the Paraiba Basin, Northeastern Brazil: Landform, sea level and tectonics in Eastern South America passive margin

Late Quaternary deposits in the northeastern Brazil have been scarcely investigated, despite their relevance to the discussion of the post-rift evolution of the South American passive margin within the context of landform, sea level and tectonic deformation. Sedimentological, stratigraphic and morphological characterization of these deposits, referred as Post-Barreiras Sediments, led to their distinction from underlying Early/Middle Miocene strata. Based on optically stimulated luminescence (OSL) dating, two sedimentary units (PB1 and PB2) were recognized and related to the time intervals between 74.8 +/- 9.3 and 30.8 +/- 6.9 ka, and 8.8 +/- 0.9 and 1.8 +/- 0.2 ka, respectively. Unit PB1 consists of indurated sandstones and breccias either with massive bedding or complex types of soft sediment deformation structures generated by contemporaneous seismic activity. Unit PB2 is composed of massive sands or sands related to structures developed by dissipation of dunes. The present work, focusing on the Post-Barreiras Sediments, discusses landform, sea level and tectonics of the eastern South American passive margin during the latest Quaternary. Non-deposition and sub-aerial exposure related to the Tortonian worldwide low sea level combined with tectonic quiescence followed the Miocene transgression. Tectonic deformation in the latest Pleistocene created space to accommodate unit PB1 in downthrown faulted blocks and, perhaps, also synclines produced by strike-slip deformation. Although deposition of this unit was simultaneous with the progressive fall in sea level that followed the Last Interglacial Maximum, punctuated rises combined with land subsidence led to marine deposition close to the modern coastline. Renewed subsidence in the Holocene gave rise to accommodation of the Post-Barreiras Sediments. Most of unit PB2 was deposited during the Holocene Transgression, but it is not composed of marine sediments, which suggests either an insignificant rise in relative sea level or aeolian reworking of thin transgressive sands. The data presented here lead to a review of the evolution of the South American passive margin based on assumptions of uniform sedimentation and undeformed planation surfaces over a wide coastal area of the northeastern Brazil. (C) 2011 Elsevier B.V. All rights reserved.

Sediment deformation in Miocene and post-Miocene strata, Northeastern Brazil: Evidence for paleoseismicity in a passive margin

Stratigraphic intervals characterized by varied and complex styles of soft-sediment deformation structures are well preserved in Miocene and Late Pleistocene to Holocene deposits of a sedimentary basin located in Northeastern Brazil. The Miocene strata, represented by the Barreiras Formation, record only brittle structures, including numerous faults and fractures with straight and high angle-dipping planes that are often filled with sands derived from overlying beds. Folds consisting of broad anticlines and synclines are also present in this unit. The late Pleistocene to Holocene deposits, named Post-Barreiras Sediments, contain an indurated sandy package with a large variety of ductile and brittle deformation structures (i.e., massive sandstones with isolated sand fragments and breccias, undulatory strata, sand dykes and diapirs, sinks and bowls, pebbly pockets, plunged sediment mixtures, fitted sand masses, cone-shaped cracks, fault grading and sedimentary enclaves). These features, confined to sharp-based stratigraphic horizons that progressively grade downward into undisturbed deposits, are related to seismic shocks of high surface-wave magnitude (i.e., Ms>5 or 6). Amalgamated seismites suggest that previously formed seismites were affected by subsequent seismic-wave propagation. Seismic waves caused by activity along one, or most likely, several tectonic structures would have propagated throughout the depositional environment, producing laterally extensive seismites. The close proximity to earthquake epicenters would have promoted pervasive re-sedimentation due to pore overpressure, resulting high volumes of massive sandstones and breccia. The similarity between deposits with correlatable strata from many other areas along the Brazilian coast allows raise the hypothesis that the seismic episodes might have affected sedimentation patterns in a large (i.e., extension of several hundreds of kilometers) geographic area. Thus, the modern seismicity recorded along Northeastern Brazil was recurrent during the Quaternary and, perhaps, also in the Pliocene. The estimated high magnitude of the seismic events and the great regional extent of the affected area demonstrate that the Brazilian coast experienced tectonic stress through the last geological episodes of its evolution, which would have favored sediment accumulation and penecontemporaneous re-sedimentation. This geological context is unexpected in a passive margin, inducing to revisit the debate on how active is a passive margin. (C) 2010 Elsevier B.V. All rights reserved.

Denudation history of the Bocaina Plateau, Serra do Mar, southeastern Brazil: Relationships to Gondwana breakup and passive margin development

The Bocaina Plateau, which is situated on the eastern flank of the continental rift of southeastern Brazil, is the highest part of the Serra do Mar. Topographic relief in this area is suggested to be closely related to its complex tectono-magmatic evolution since the breakup of Western Gondwana and opening of the South Atlantic Ocean. Apatite fission track ages and track length distributions from 27 basement outcrops were determined to assess these hypotheses and reconstruct the denudation history of the Bocaina Plateau. The ages range between 303 +/- 32 and 46 +/- 5 Ma, and are significantly younger than the stratigraphic ages. Mean track lengths vary from 13.44 +/- 1.51 to 11.1 +/- 1.48 mu m, with standard deviations between 1.16 and 1.83 mu m. Contrasting ages within a single plateau and similar ages at different altitudes indicate a complex regional tectonothermal evolution. The thermal histories inferred from these data imply three periods of accelerated cooling related to the Early Cretaceous continental breakup, Early Cretaceous alkaline magmatism, and the Paleogene evolution of the continental rift of southeastern Brazil. The oldest fission track ages (>200 Ma) were obtained in the Serra do Mar region, suggesting that these areas were a long-lived source of sediments for the Parana, Bauru, and Santos basins. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Quaternary tectonics in a passive margin: Marajo Island, northern Brazil

Marajo Island is located in a passive continental margin that evolved from rifting associated with the opening of the Equatorial South Atlantic Ocean in the Late Jurassic/Early Cretaceous period. This study, based on remote sensing integrated with sedimentology, as well as subsurface and seismographic data available from the literature, allows discussion of the significance of tectonics during the Quaternary history of marginal basins. Results show that eastern Marajo Island contains channels with evidence of tectonic control. Mapping of straight channels defined four main groups of lineaments (i.e. NNE-SSW, NE-SW, NW-SE and E-W) that parallel main normal and strike-slip fault zones recorded for the Amazon region. Additionally, sedimentological studies of late Quaternary and Holocene deposits indicate numerous ductile and brittle structures within stratigraphic horizons bounded by undeformed strata, related to seismogenic deformation during or shortly after sediment deposition. This conclusion is consistent with subsurface Bouguer mapping suggestive of eastern Marajo Island being still part of the Marajo graben system, where important fault reactivation is recorded up to the Quaternary. Together with the recognition of several phases of fault reactivation, these data suggest that faults developed in association with rift basins might remain active in passive margins, imposing important control on development of depositional systems. Copyright (C) 2007 John Wiley & Sons, Ltd.

Pseudomonas aeruginosa PA14 cupD transcription is activated by the RcsB response regulator, but repressed by its putative cognate sensor RcsC

The opportunistic pathogen Pseudomonas aeruginosa PA14 possesses four fimbrial cup clusters, which may confer the ability to adapt to different environments. cupD lies in the pathogenicity island PAPI-1 next to genes coding for a putative phosphorelay system composed of the hybrid histidine kinase RcsC and the response regulator RcsB. The main focus of this work was the regulation of cupD at the mRNA level. It was found that the HN-S-like protein MvaT does not exert a strong influence on cupD transcript levels, as it does for cupA. cupD transcription is higher in cultures grown at 28 degrees C, which agrees with a cupD mutant presenting attenuated virulence only in a plant model, but not in a mouse model of infection. Whereas an rcsC in-frame deletion mutant presented higher levels of cupD mRNA, rcsB deletion had the opposite effect. Accordingly, overexpression of RcsB increased the levels of cupD transcription, and promoted biofilm formation and the appearance of fimbriae. A single transcription start site was determined for cupD and transcription from this site was induced by RcsB. A motif similar to the enterobacterial RcsB/RcsA-binding site was detected adjacent to the -35 region, suggesting that this could be the RcsB-binding site. Comparison of P. aeruginosa and Escherichia coli Rcs may provide insights into how similar systems can be used by different bacteria to control gene expression and to adapt to various environmental conditions.

Reliable and fast sensor for in vitro evaluation of solar protection factor based on the photobleaching kinetics of a nanocrystalline TiO(2)/dye UV-dosimeter

A reliable and fast sensor for in vitro evaluation of solar protection factors (SPFs) of cosmetic products, based on the photobleaching kinetics of a nanocrystalline TiO(2)/dye UV-dosimeter, has been devised. The accuracy, robustness and suitability of the new device was demonstrated by the excellent matching of the predicted and the in vivo results up to SPF 70, for four standard samples analyzed in blind. These results strongly suggest that our device can be useful for routine SPF evaluation in laboratories devoted to the development or production of cosmetic formulations, since the conventional in vitro methods tend to exhibit unacceptably high errors above SPF similar to 30 and the conventional in vivo methods tend to be expensive and exceedingly time consuming. (C) 2011 Elsevier B.V. All rights reserved.

Vanadium oxide-porphyrin nanocomposites as gas sensor interfaces for probing low water content in ethanol

Vanadium pentoxide xerogels (VXG) incorporating meso(3- and 4-pyridyl)porphyrin cobalt(III) species coordinated to four [Ru(bipy)(2)Cl](+) complexes were employed as gas sensing materials capable of detecting small amounts of water in commercial ethanol and fuel supplies. According to their X-ray diffraction data, the original VXG lamellar framework was maintained in the nanocomposite material, but the interlamellar distance increased from 11.7 to 15.2 angstrom, reflecting the intercalation of the porphyrin species into the vanadium pentoxide matrix. The films generated by direct deposition of the nanocomposite aqueous suspensions exhibited good electrical and electrochemical performance for application in resistive sensors. The analysis of water in ethanol and fuels was carried out successfully using an especially designed electric setup incorporating a laminar gas flow chamber and interdigitated gold electrodes coated with the nanocomposites. (C) 2010 Elsevier B.V. All rights reserved.