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X-ray stereo digital image correlation (DIC) measurements were performed at 10 kHz on the internal surface of a jointed structure in a shock tube at a shock Mach number of 1.42 and compared with optical stereo DIC measurements on the outer, visible surface of the structure. The shock tube environment introduces temperature and density gradients in the gas through which the structure was imaged, resulting in spatial and temporal index of refraction variations. These variations cause bias errors in optical DIC measurements due to beam-steering but have minimal influence on x-ray DIC measurements. These results demonstrate the utility of time-resolved x-ray DIC measurements in complicated environments where optical measurements suffer severe errors and/or are precluded by lack of optical access.

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by impaired glucose homeostasis, insulin resistance and hyperglycemia. Among its serious multisystemic complications is diabetic retinopathy (DR), which develops slowly and often insidiously. This disorder-the most common cause of vision loss in working-age adults-is characterized by functional and morphological changes in the retina. It results from the exacerbation of ischemic and inflammatory conditions prompted by alterations in the blood vessels, such as the development of leukostasis, thickening of the basement membrane, retinal neovascularization and fibrovascular tissue formation at the vitreoretinal interface. The pathogenic alterations are usually triggered at the biochemical level, involving a greater activity in 4 pathways: the polyol pathway, the hexosamine pathway, the formation of advanced glycation end-products and the activation of protein kinase C isoforms. When acting together, these pathways give rise to increased levels of reactive oxygen species and decreased levels of endogenous antioxidant agents, thus generating oxidative stress. All current therapies are aimed at the later stages of DR, and their application implies side effects. One possible strategy for preventing the complications of DM is to counteract the elevated superoxide production stemming from a high level of blood glucose. Accordingly, some treatments are under study for their capacity to reduce vascular leakage and avoid retinal ischemia, retinal neovascularization and macular edema. The present review summarizes the biochemical aspects of DR and the main approaches for treating it.

Modelling the failure of engineering polymers used in critical structural applications is still a challenging task that is increasingly demanded by the industry to optimize part design and estimate component service life. The difficulties include not only developing constitutive models capable of reproducing the complex polymer response at a reasonable computational cost, but also calibrating related parameters. That is to say, a way to find specific parameters which best represent the actual behavior of a material within the scope and limitations of a given constitutive or failure model. The aim of this study is to contribute in developing a robust inverse method calibration strategy. To address this issue, a novel approach based on genetic algorithms optimization (GA) together with finite element analysis (FEA) is proposed to blindly extract key constitutive and failure parameters from instrumented impact tests on single edge notched bending (SENB) specimens. The method was implemented to infer eight constitutive and failure parameters of a polyamide 12 (PA12) with an elasto-plastic ductile damage model. Triaxiality induced stable-unstable transition was successfully achieved by varying the notch depth of SENB specimens. Accordingly, three optimization schemes were conducted: (i) using only unstable experimental data; (ii) using only stable experimental data and (iii) using both simultaneously (multi-objective). The set of parameters obtained from each scheme were used to perform predictive FEA simulations, which were verified with experimental data. It was proven that both propagation regimes provide substantial information to obtain the mechanical response of the material. Simulation results evidenced the capability of the proposed strategy to predict the PA12 impact response and furthermore to fairly reproduce a completely different load case: a dynamic tensile test.

Digital Image Correlation (DIC) is a well-established, non-contact diagnostic technique used to measure shape, displacement and strain of a solid specimen subjected to loading or deformation. However, measurements using standard DIC can have significant errors or be completely infeasible in challenging experiments, such as explosive, combustion, or fluid-structure interaction applications, where beam-steering due to index of refraction variation biases measurements or where the sample is engulfed in flames or soot. To address these challenges, we propose using X-ray imaging instead of visible light imaging for stereo-DIC, since refraction of X-rays is negligible in many situations, and X-rays can penetrate occluding material. Two methods of creating an appropriate pattern for X-ray DIC are presented, both based on adding a dense material in a random speckle pattern on top of a less-dense specimen. A standard dot-calibration target is adapted for X-ray imaging, allowing the common bundle-adjustment calibration process in commercial stereo-DIC software to be used. High-quality X-ray images with sufficient signal-to-noise ratios for DIC are obtained for aluminum specimens with thickness up to 22.2 mm, with a speckle pattern thickness of only 80 μm of tantalum. The accuracy and precision of X-ray DIC measurements are verified through simultaneous optical and X-ray stereo-DIC measurements during rigid in-plane and out-of-plane translations, where errors in the X-ray DIC displacements were approximately 2–10 μm for applied displacements up to 20 mm. Finally, a vast reduction in measurement error—5–20 times reduction of displacement error and 2–3 times reduction of strain error—is demonstrated, by comparing X-ray and optical DIC when a hot plate induced a heterogeneous index of refraction field in the air between the specimen and the imaging systems. Collectively, these results show the feasibility of using X-ray-based stereo-DIC for non-contact measurements in exacting experimental conditions, where optical DIC cannot be used.

INTRODUCTION The number of variables that influence the success of an ACL reconstruction is such that, the use of numerical tools becomes increasingly necessary. In this work, a finite element model is developed to simulate the ACL reconstruction in its tibial insertion. MATERIAL AND METHODS Tibiae and ligaments porcine samples were used in this work. As the tibial fixation, an interference screw with a nominal diameter of 7mm and a length of 25mm is used. The plasty which replace the injured ligament was characterize using tensile tests. Uniaxial and confined compression tests, as well as indentation tests, were used for characterizing trabecular bone. Finite element methods were used for the implementation of the ACL reconstruction simulation, which studies the effect in the knee joint of all the elements involved (plasty, bone and interference screw). RESULTS None of the models available for the description of the trabecular bone behavior (von Mises, Hill and Crushable Foam), is capable of doing it in a completely proper manner. The use of one or the other constitutive model does not greatly influence the numerical simulation results. CONCLUSIONS As trabecular bone has a strongly anisotropic and non-symmetric mechanical behavior, none of the constitutive models available in the finite element code used is capable of fully describing it. Thus, the use of von Mises criterion is recommended, as it is the easiest to define and the one that requires the least numerical resources (lower computational cost).

This paper reports results from a single-hologram beamsteering system that uses multi-plane hologram generation to allow simultaneous beamsteering of the red and green components of white light. Gigabit-per-second transmission is demonstrated using eye-safe levels of optical power.

Phosphor thermometry has been successfully applied within several challenging environments. Typically, the thermographic phosphors are excited by an ultraviolet light source, and the temperature-dependent spectral or temporal response is measured. However, this is challenging or impossible in optically thick environments. In addition, emission from other sources (e.g., a flame) may interfere with the optical phosphor emission. A temperature dependent x-ray excitation/emission could alleviate these issues as x-rays could penetrate obscurants with no interference from flame luminosity. In addition, x-ray emission could allow for thermometry within solids while simultaneously x-ray imaging the structural evolution. In this study, select thermographic phosphors were excited via x-ray radiation, and their x-ray emission characteristics were measured at various temperatures. Several of the phosphors showed varying levels of temperature dependence with the strongest sensitivity occurring for YAG:Dy and ZnGa2O4:Mn. This approach opens a path for less intrusive temperature measurements, particularly in optically opaque multiphase and solid phase combustion environments.

In this letter, we present the design and implementation of a pixelated electro-absorption modulator-based modulating retroreflector (MRR) for high-speed optical wireless communications. The modulator is based on a multiple quantum well structure embedded in an asymmetric Fabry–Perot cavity. This MRR was used in an outdoor link, operating at 150 Mb/s with a bit error rate (BER) of $1.22\times 10^{-6}$ at a range of 200 m. The system was also tested in laboratory-controlled conditions achieving a data rate of 200 Mb/s with a BER of $2\times 10^{-4}$ . To the best of our knowledge, this is the fastest retroreflective free-space optics demonstration in both the indoor and outdoor environments.

Arsenic, a metalloid and naturally occurring element, is one of the most abundant elements in the earth's crust. Water is contaminated by arsenic through natural sources (underground water, minerals and geothermal processes) and anthropogenic sources such as mining, industrial processes, and the production and use of pesticides. Humans are exposed to arsenic mainly by drinking contaminated water, and secondarily through inhalation and skin contact. Arsenic exposure is associated with the development of vascular disease, including stroke, ischemic heart disease and peripheral vascular disease. Also, arsenic increases the risk of tumors of bladder, lungs, kidneys and liver, according to the International Agency for Research on Cancer and the Food and Drug Administration. Once ingested, an estimated 70-90% of inorganic arsenic is absorbed by the gastrointestinal tract and widely distributed through the blood to different organs, primarily to the liver, kidneys, lungs and bladder and secondarily to muscle and nerve tissue. Arsenic accumulates in the organs, especially in the liver. Its excretion mostly takes place through urination. The toxicokinetics of arsenic depends on the duration of exposure, pathway of ingestion, physicochemical characteristics of the compound, and affected biological species. The present review outlines of arsenic toxic effects focusing on different cancer types whit highest prevalence's by exposure to this metalloid and signaling pathways of carcinogenesis.

Type 2 diabetes (T2D), which causes many adverse effects such as endothelial dysfunction and cardiovascular disease, affects approximately 425 million people worldwide. However, about half have not yet been diagnosed. For what is recommended the use of screening tools to identify individuals at risk for T2D or in the early stages of the disease in order to impement preventive strategies or early treatment. According to a widely used survey, the FINDRISC scale, a hereditary family history of T2D (FH-T2D) is as important a risk factor as having had high glucose levels. The aim of the present study was to carry out non-probabilistic sampling in a Mexican population to evaluate key factors in the development of diabetes. The participants were divided into three groups: with and without FH-T2D and diagnosed with T2D. A comparison of the groups with and without FH-T2D revealed higher values in the former for body mass index (BMI: 24.5 vs 21.9 kg/m2), glycosylated hemoglobin [Hb1Ac: 5.775% (39 mmol/mol) vs 4.825% (29 mmol/mol)] and triglycerides (164.18 vs 68.12 mg/dL), and a lower value for the BH4/BH2 index (0.7846 vs 1.6117). These results indicate significant metabolic alterations and endothelial dysfunction for the FH-T2D group. This strongly suggests the need to screen individuals with a family history of inherited T2D based on their level of HbA1c, triglycerides and BH4.

Many industries have taken interest in the use of coal gasification for the production of chemicals and fuels. This gasification can be carried out inside a fluidized bed reactor. This non-ideal reactor is difficult to predict due to the complex physical phenomena and the different chemical changes that the feedstock undergoes. The lack of a good model to simulate the reactor’s behavior produces less efficient processes and plant designs. Various approaches to the proper simulation of such reactor have been proposed. In this paper, a new model is developed for the simulation of a pressurized bubbling fluidized bed (PBFB) gasifier that rigorously models the physical phenomena and the chemical changes of the feedstock inside the reactor. In the model, the reactor is divided into three sections; devolatilization, volatile reactions and combustion-gasification. The simulation is validated against experimental data reported in the literature and compared with other models proposed by different authors; once the model is validated, the dependence of the syngas composition on operational pressure, temperature, steam/coal and air/coal ratios are studied. The results of this article show how this model satisfactorily predicts the performance of PBFB gasifiers.

In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with (18)F, (13)N or (68)Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

In this paper, we describe an optical wireless communications system that uses light from an optical fibre access point to provide transparent and bi-directional optical links to nomadic terminals. Full localization and tracking is implemented, and a 50 Gb/s link is demonstrated. The link operates in an indoor environment, with a $ \pm 30^\circ $ field-of-view covering a distance of up to 3 m, and a localization accuracy of 0.05° (2.5 mm pointing accuracy at 3 m) is achieved. This demonstration shows that it is feasible to use an automated system to achieve the required alignment for an ultrahigh data rate fibre-wireless-fibre link.

An increase in the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) leads to complications during chronic kidney disease (CKD). This increase essentially derives from the impairment of natural antioxidant systems of the organism. The resulting oxidative stress produces damage to kidney tissue, especially by affecting nephrons and more generally by disrupting the function and structure of the glomerulus and interstitial tubule. This leads to a rapid decline in the condition of the patient and finally renal failure. Possible causes of kidney tissue damage are explored, as are different therapies, especially those related to the administration of antioxidants.

Background:Few patients have been described in the literature with mutations in the Lacasa Domain containing one (LACC1) gene. Its clinical presentation usually associates sustained systemic inflammation associated with chronic polyarticular erosive arthritis. Until now, there have been multiple treatments described to try to control the disease, however, they are generally unsuccessful in the long term.Objectives:Describe the clinical course of a patient as well as the different treatments usedMethods:Clinical chart reviewResults:Female 18-year-old born from a consanguineous Moroccan couple. Mother, brother and sister with similar conditions. She started at 3 years with fever, anemia, intense elevation of acute phase reactants and symmetric polyarthritis (knees, elbows, carps, shoulders, hands and ankles). Subsequent whole exome sequencing identified c.128_129delGT mutation in the LACC1/FAMIN gene. During the course of her illness, she has received treatment with oral, intravenous and infiltrated corticosteroid, methotrexate and etanercept, without getting adequate control of the disease. In 2016, she started treatment with tocilizumab (8 mg / kg every two weeks), obtaining an acceptable control of the disease (requiring periodic infiltrations every 2-3 months due to persistent arthritis). Nonetheless, in April 2019, she consulted for clinical worsening of the arthritis and laboratory test (C reactive protein 99.7 mg / L, erythrosedimentation rate 53 mm / h, leukocytes 13,500/µL and neutrophils 10,930/µL). At that time, she discontinued therapy with tocilizumab and started tofacitinib 5 mg every 12 hours with good evolution. Since its introduction, it has not required joint infiltration again and the inflammatory parameters (persistently elevated previously) have normalized.Conclusion:The jak kinasa inhibitors may be a treatment option in those patients with bad response to conventional therapy.References:[1]Rabionet R, Remesal A, Mensa-Vilaró A, Murías S, Alcobendas R, González-Roca E, Ruiz-Ortiz E, Antón J, Iglesias E, Modesto C, Comas D, Puig A, Drechsel O, Ossowski S, Yagüe J, Merino R, Estivill X, Arostegui JI. Biallelic loss-of-function LACC1/FAMIN Mutations Presenting as Rheumatoid Factor-Negative Polyarticular Juvenile Idiopathic Arthritis. Sci Rep. 2019 Mar 14;9(1):4579Disclosure of Interests:None declared

Background Exercise-induced stress induces considerable changes in the immune system. To better understand the mechanisms related to these immune changes during acute and chronic physical stress, we studied the effects of aerobic physical training (APT) on several parameters of the immune system. Methods Previously untrained males (18-25 years of age) were divided into a group that was subjected to 6 months of APT (N.=10) and a sedentary control group (N.=7). The subjects performed a cardiopulmonary exercise test (CET) at 0, 3, and 6 months of the APT program. B cell (CD19+), T cell (CD4+ and CD8+), and natural killer cell (CD56+) levels, and mitogen-induced T cell proliferation and cytokine production (interleukin-1, interleukin-4, interleukin-12, and interferon-γ) were evaluated before and at 30 seconds and 24 hours after the CET. Results There was a significant increase in CD4+ T cells and natural killer cells and a significant reduction in T cell proliferation in both groups 30 seconds after the CET at 0, 3 and 6 months of the APT program. Of note, the trained group showed significantly lower resting T cell proliferation (before and 24 hour after the CET) than the sedentary control groups at 0, 3 and 6 months of the APT program. There were no significant differences in cytokine production after the CET between both groups at any time point of the APT program. Conclusions These data show that APT does not condition against strenuous exercise-induced immune changes but significantly modulates T cell proliferative responses.

In this work we present an ultra-wide coverage visible light communication (VLC) system based on a mechanical beam steering system at the transmitter terminal and a fluorescent optical concentrator at the receiver. The transmitter and receiver full field of view (FFOV) are 100° and 120°, respectively. The coverage area of the transmitter system at 2m is 12.5m2 and a data link of 300Mbps has been achieved at this range. Postprint

Optical fiber communication networks can provide terabit aggregate capacities to buildings and offices within modern cities. Practical wireless systems are orders of magnitude below this capacity. In this letter, we describe an indoor optical bidirectional wireless link with an aggregate capacity over 100 Gb/s. The link operates over ~3 m range at 224 Gb/s (6 x 37.4 Gb/s) and 112 Gb/s (3 x 37.4 Gb/s) with a wide field of view (FOV) of 60° and 36°, respectively. To the best of our knowledge, this is the first demonstration of a wireless link of this type with a FOV that offers practical room-scale coverage.

The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO1 system, “advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects”, and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.

This paper explores the use of a reading lamp as an access point for a Visible Light Communications (VLC) downlink channel. We have established an infrared uplink channel based on a network adapter, supporting both a VLC receiver and an infrared emitter. The optical signal power distribution over the passenger area has been also studied using a Monte Carlo Ray-Tracing algorithm. The hardware implementation and testing results are also presented.

Weight reduction and low power consumption are key requirements in the next generation of unmanned aerial vehicles (UAVs). To communicate with an operator, a secured link between the UAV and a ground base station is desirable. To realise these links, retroreflecting free space optics is potentially attractive as it offers light-weight and low complexity at the UAV. However, the base station requires a high performance tracking module to enable a steady illumination of the UAV retroreflector. In this paper, we present the design and implementation of a tracking system, which consists of coarse tracking and holographic fine tracking modules working cooperatively. Using this system, experimental field trials were carried out by mounting a multiple quantum well (MQW) based modulated retro-reflector (MRR) on a commercial UAV. A 2 Mbps optical link was achieved with a bit error rate of ~2x10^-4 at a link range of 300m.

Fibre-to-the-home deployment is enabling ultra-high speed communications to reach the end-user in many cities. Most users would like to access this capacity using wireless devices. However, available wireless technologies can handle data rates often many orders of magnitude slower than those potentially offered by the fibre infrastructure. This paper describes an optical wireless architecture that bridges this gap by using the light directly from the fibre to create an indoor point-to-multipoint transparent distribution system. The approach is all optical, thus inherently independent of the data-rate and modulation formats. A holographic beamsteering device is used to direct narrow 1550 nm beams to the receivers' locations. Specifically, a spatial light modulator (SLM), assisted by angle magnification optics allowed for a ±30° field-of-view coverage in both the horizontal and vertical directions. In this work we experimentally study two different methods to generate the point-to-multipoint capability: spatial division of the SLM in independent phaseprogrammable regions and the Gerchberg-Saxton (GS) multipoint hologram generation algorithm. These methods were compared for a 2-beam beamsteering system at a range of ~ 2 meters. Results show that the spatial division approach creates more stable links with higher optical margins. However, the GS-based steering offers a more scalable solution for a point-to-multipoint architecture that addresses a large number of end-users.

Determining the diagnosis of Crohn’s disease has been highly difficult mainly during the first years of this study carried out at the Pontificia Universidad Catolica (PUC) Clinical Hospital. For instance, it has been frequently confused with Irritable bowel syndrome and sometimes misdiagnosed as ulcerative colitis, infectious colitis or enterocolitis, intestinal lymphoma, or coeliac disease. Consequently, it seems advisable to characterize what the most relevant clinical features are, in order to establish a clear concept of Crohn's disease. This difficulty may still be a problem at other medical centers in developing countries. Thus, sharing this information may contribute to a better understanding of this disease. Based on the clinical experience gained between 1963 and 2004 and reported herein, the main clinical characteristics of the disease are long-lasting day and night abdominal pain, which becomes more intense after eating and diarrhoea, sometimes associated to a mass in the abdomen, anal lesions, and other additional digestive and nondigestive clinical features. Nevertheless, the main aim of this work has been the following: is it possible to make, in an early stage, the diagnosis of Crohn's disease with a high degree of certainty exclusively with clinical data?

We experimentally characterize a transparent and bidirectional fibre-wireless-fibre link with a wide field-of-view >60° (full-cone) at a transceivers' range of ~ 3 metres. The potential for indoor Terabit data rate via wavelength division multiplexing techniques is demonstrated. The use of single-mode vs multi-mode fibres is also explored using a holographic beamsteering setup. The angular steering accuracy required for the multi-mode fibre is found to be ~ 1° compared to ~ 0.1° for the single-mode.

In this paper we describe the implementation of a prototype of an optical wireless system based on visible white LED lamps, which allows a video broadcasting to reach a bit rate of 2 Mbps. This technology is usually called VLC or Visible Light Communications and presents several advantages as the robustness against EM interference, safety for human eye and security against undesired network access. These conditions make this system suitable for co-existing with commercial RF networks -WiFi, Bluetooth, etc.-, especially for in-house applications. For the uplink channel we have also included in the prototype an infrared 115 kbps transceiver. This VLC system could be used for supporting data transmission applied to low-speed sensor network connections as well. The electronic structure of a low-cost VLC transceiver, based on commercial off-the-shelf components and LED lamps is presented too. The modulation process and the Ethernet interface implemented in each access point are also described. Finally, some conclusions and application scenarios are drawn.

Several years ago Canary Islands have an Energy Plan PECAN, but that Plan was not fulfilled due to lack of land for the different infrastructures. It has been necessary to prepare an Territorial Plan for Energy Infrastructures of each isle, we try to present the procedure followed.

This paper describes an optical wireless system based on time-hopping spread-spectrum techniques, as a first approach, at infrared wavelengths. It can be used either for low-speed sensor interconnections or as a return channel in a visible light communications system. The main advantage of this scheme is an improvement in the narrowband interference rejection capability and the number of simultaneous users supported, compared with other wireless optical standards. Moreover, a wide analysis is carried out about the mutual interference between time-hopping spread-spectrum systems and other infrared ones. Finally, some conclusions are drawn about some design parameters of the time-hopping system in order to allow its compatibility with preexisting optical devices.

Objective Augmented reality (AR) is a technique in which an overlay of a virtual image to a live picture is performed to create a new image in which both original images coexist as a single image. This results in the visualization of internal structures through overlying tissues. The objective was to describe an easy, inexpensive, and successful method to coregister with AR in an image-guided surgery setting using the resources at hand. Methods Cortical information was obtained with a volumetric acquisition of 200 0.8-mm thick, cerebral magnetic resonance imaging scans in an axial T1-weighted sequence. For the venous anatomy, a contrast phase at 7 mm/s velocity was used. This data was reconstructed in a three-dimensional fashion using MRIcro software (v. 1.37, freeware, courtesy of Chris Rorden) and was overlaid to a digital image of the cerebral cortex either pre- or intraoperatively. Results Eight patients were studied. There was an adequate coregistration in seven of the patients as confirmed by intraoperative ultrasound, frame-based stereotaxy, or obvious anatomic homology between the three-dimensional magnetic resonance imaging scan virtual reconstruction and the live image obtained during surgery. AR was not possible in one case of a cerebellar lesion. Conclusion AR coregistration capabilities are adequate when revised by other intraoperative guidance devices. When performed with "freeware" software and conventional digital cameras, it is relatively inexpensive, which makes it a potential tool for surgical planning and noncontinuous intraoperative guidance in neurosurgery. Its largest drawbacks are the inability to function in deep-seated lesions and its lack of tracking devices, which gives it a noncontinuous coregistration nature.

The Optical, Spectroscopic, and Infrared Remote Imaging System OSIRIS is the scientific camera system onboard the Rosetta spacecraft (Figure 1). The advanced high performance imaging system will be pivotal for the success of the Rosetta mission. OSIRIS will detect 67P/Churyumov-Gerasimenko from a distance of more than 106 km, characterise the comet shape and volume, its rotational state and find a suitable landing spot for Philae, the Rosetta lander. OSIRIS will observe the nucleus, its activity and surroundings down to a scale of ~2 cm px−1. The observations will begin well before the onset of cometary activity and will extend over months until the comet reaches perihelion. During the rendezvous episode of the Rosetta mission, OSIRIS will provide key information about the nature of cometary nuclei and reveal the physics of cometary activity that leads to the gas and dust coma. OSIRIS comprises a high resolution Narrow Angle Camera (NAC) unit and a Wide Angle Camera (WAC) unit accompanied by three electronics boxes. The NAC is designed to obtain high resolution images of the surface of comet 67P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range 250–1000 nm at an angular resolution of 18.6 μrad px−1. The WAC is optimised to provide images of the near-nucleus environment in 14 discrete filters at an angular resolution of 101 μrad px−1. The two units use identical shutter, filter wheel, front door, and detector systems. They are operated by a common Data Processing Unit. The OSIRIS instrument has a total mass of 35 kg and is provided by institutes from six European countries. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Sweden (SNSB), and Spain (MEC) is gratefully acknowledged. Substantial support for the development of the Data Processing Unit was provided by the ESA Technical Directorate through the Technical Research Programme. In addition to the formal co-authors of this paper (comprising lead scientists, Co-Is, project managers, and lead engineers ), the project was supported by an enormous number of scientists, engineers, and technicians involved in the day-to-day development of the hardware. These include J. C. Blanc, D. Pouliquen, M. Saisse (France), A. Alvarez, A. L. Arteaga, A. Carretero, M. Fernández, H. Guerrero, P. Gutiérrez, J. L. Lizondo, V. Luengo, J. A. Martín, M. A. Martín, J. Meseguer, J. M. Mi, L. Moreno, J. Navarro, A. Núñez, E. Ragel, D. Rodríguez, G. Rosa, A. Sanchez, J. C. Sanmartín, G. Tonellotto (Spain), W. Boogaerts, W. Engelhardt, K. Eulig, B. Fiethe, A. Fischer, M. Gartner, K. Grabig, K. Kellner, A. Kiihn. W. Kiihn. J. Knollenberg, W. Neumann, J. Nitsch, P. Rüffer, H. Schüddekopf, U. Schiihlc. I. Sebastian, S. Stelzer, U. Strohmeyer, T. Tzscheetzsch, M. Wassermeyer (Germany), B. Johlander (ESTEC), M. Baessato, P. F. Brunello, S. Casotto, F. Don-, M. Lazzarin, E. Marchetti, F. Marzari, P. G. Nicolosi, F. Perón, F. Rampazzi, B. Saggin, G. Tondello, S. Verani, P. Zambolin ' (Italy), J. Lagerros, and B. Davidsson (Sweden). Peerreview

ResumenEste trabajo persigue identificar y medir la incidencia conjunta de las concentraciones geográficas y las redes de cooperación en la capacidad de las empresas de alta tecnología para completar los recursos y competencias esenciales en sus procesos de innovación. Para ello, se ha formulado y contrastado un conjunto de hipótesis mediante el estudio de una muestra de empresas biotecnológicas. Como resultado, se obtienen conclusiones interesantes sobre el efecto de la localización y las alianzas en el acceso de estas empresas a recursos y competencias clave tales como conocimiento científico y tecnológico, personal altamente cualificado, competencias complementarias de producción y comercialización, apropiabilidad y recursos financieros externos; asimismo se examina la relación existente entre estos factores y el rendimiento innovador.AbstractThis paper aims to measure the joint influence of geographic concentration and strategic alliances on the capacity of high-technology firms to complete key resources and competences for their innovation processes. A set of hypotheses are contrasted through a study carried out within a sample of biofirms. As a result, interesting conclusions about the effect of location and alliances on accessing key resources and competences such as scientific and technological knowledge, skilled labour, complementary downstream competences, appropriability and external financial resources; likewise, the relationship between these factors and innovation performance is examined.

Around 1,100 million people they do not have access to an improved water provision, and more than 2,600 million people they lack access to improved services of cleaning. The water shortage affects to approximately between 1,000 and 2,000 million people anywhere in the world. From 1960, the difference between water use and accessible provision have increased in a 20% per decade. The desert ground affects means of subsistence of million people, including a great amount of the poor men of dry earth.[1] FAO's recent report World agriculture: towards 2015/30 projects that global food production will need to increase by 60% to close nutrition gaps, cope with the population growth and accommodate changes in diets over the next three decades. Water withdrawals for agriculture are expected increase by some 14% in that period, representing an annual growth rate of 0.6%, down from 1.9% in the period 1963-1999. Much of the increase will take place on arable irrigated land, forecast to expand globally from some 2 million sq. km to 2.42 million sq. km. In a group of 93 developing countries, water use efficiency in irrigation i.e. the ratio between water consumption by crops and the total amount of water withdrawn is expected to grow from an average 38% to 42%. The water needs of humans and animals are relatively small the average human drinks about four litres a day. But producing the same person's daily food can take up to 5,000 litres of water.

This work describes the application of the Lattice Fringe Spacing Measurement (LFSM) method to the study of complex multiquantum well heterostructures containing both low-misfit and strain compensated short period superlattices in barriers and wells, respectively. 90º-wedge cross-sectional samples have been used. The adequate choice of both experimental conditions and digitized sampling allows the whole heterostructure to be visualized and studied in a single High Resolution Transmission Electron Microscopy (HRTEM) image. Sample preparation and image processing technique are simple and inexpensive, resulting a fast procedure particularly suited for the analysis of large areas. By this way, in a single HRTEM image we have measured, in the growth direction, the lattice spacings at either side of the multiple grown interfaces as well as the period variations of both types of superlattices; in addition, we have measure on the same image the lattice strain in a direction perpendicular to the growth direction by using the LFSM and the Cumulative Sum methods. We have observed local lateral variations within the wells, with regions tensile or compressively strained, while a vestige of the grown SL remains, indicating the occurrence of a strain induced lateral composition modulation process spontaneously produced during the growth of strain compensated short-period superlattices. This is further confirmed in cross-section prepared by the tripod mechanical polisher method., The authors express their sincere thanks to A. Guerrero for his support in the CUSUM program, to J. Thibault who invited them to take benefit of the 4000EX microscope available in the CEN-Grenoble, and to A. Sanz-Hervás, from Depto. Tecnología Electrónica, E.T.S.I.T.-U.P.M., Madrid, for his support in XRD measurements.

The lateral composition modulation of strain compensated (GaInP)m(GaInAs)m short-period superlattices (SPSL) has been investigated. Transmission electron microscopy results show that long-range lateral composition modulation is formed in m=2 SPSL grown at 400°C by atomic layer molecular beam epitaxy. The evolution of photoluminescence (PL) peak with temperature shows a blue shift with increasing temperature; in addition, low-temperature PL is strongly polarized. These properties are attributed to the lateral composition modulation. Quantum wires (QWRs) were formed using (GaInP)m(GaInAs)m SPSL as quantum wells in a multiquantum well heterostructure. The formation of QWR is confirmed by their PL properties. © 2003 Elsevier Science B.V. All rights reserved.

The new generation of UAVs (Unmanned Aerial Vehicles) require high speed data links to offload all its sensors data. RFSO (Reflective Free Space Optics) has become an important alternative to RF systems because it is robust against interception and jamming, enhancing data security. Moreover, the weight and power consumption of the RFSO coms module is reduced, making it suitable for SWaP (Size, Weight, and Power) constrained applications. In this paper, we present the design of a tracking module based on a non-mechanical holographic beam steering system. A highly accurate position sensing unit is required to accomplish a good tracking process and therefore guarantee the data link stability. Different localization methods such as centroid, centroid windowed or centroid squared are tested and compared using real data captured in a turbulent scenario. Errors below 8cm are reported in a double pass 1km link.

In this work, a complete interface between Ethernet and Visible Light Communications (VLC) networks is presented. It requires the use of previously proposed DPPM schemes for this kind of applications, but with some modifications so as to keep constant duty cycle in order to assure its use in illumination facilities. The prototype has been tested using a 2Mbps VLC Link, obtaining distances of, at least, 3 meters in an interfering environment. The PPM characteristics allow transmission without severe signal degradation on this environment. This Ethernet-VLC interface is intended to demonstrate the capability of IP broadcast applications of this kind of devices. This interface performs packing functions and flow control.

In this clinical study, five consecutive referrals to a cognitive rehabilitation therapy (CRT) programme were followed in a longitudinal protocol involving a resting SPECT and neuropsychological evaluation at pre-treatment, post-treatment, and post non-treatment intervals. All clients had acquired brain injury and initially demonstrated neuropsychological deficits and various degrees of hypoperfusion on SPECT. Statistical Parametric Mapping (SPM) was used to evaluate change in successive SPECT images. Following CRT, all clients were able to return to productive employment or schooling. Examination of the neuropsychological testing results revealed significant improvement in performance following CRT which were generally maintained during the non-treatment period. SPM analysis of the SPECT data revealed that, in a majority of cases, most of the significant increases in relative cerebral blood flow redistribution were seen during the treatment period, rather than the non-treatment period. The results suggest that, even in individuals who are more than 2 years post-brain damage, relative increases in rCBF can be demonstrated following individualized CRT and that most of these changes can be related to improvements on neuropsychological tests.

Advances in multiple view computer vision techniques have made it possible to make highly accurate three-dimensional (3D) measurements using calibrated stereo image systems. Recent experiments conducted at Sandia National Laboratories have demonstrated the feasibility of applying these techniques on an X-Ray system. Acquiring measurements from stereo image systems, be it visible or x-ray, require the estimation of the system’s intrinsic and extrinsic parameters via a calibration process. There are several calibration methods depending on the system’s configuration and its intended use. In most cases, one or more image pairs of a calibration artifact such as a 3D object of known dimension or a 2D target board are processed to estimate the system’s calibration parameters. For this paper, methods based on both types of calibration artifacts will be discussed along with experimental results.

The efficacy and safety of two polyvalent horse-derived antivenoms in Bothrops asper envenomings were tested in a randomized, double-blind, clinical trial performed in Colombia. Both antivenoms were manufactured from the same pool of hyperimmune plasma. Antivenom A was made of F(ab')2 fragments, generated by pepsin digestion and caprylic acid precipitation, whereas antivenom B consisted of whole IgG molecules produced by caprylic acid precipitation followed by ion-exchange chromatography. Besides the different nature of the active substance, antivenom B had higher protein concentration, slightly higher turbidity and aggregate content. No significant differences were observed in the efficacy of antivenoms. Both halted local and systemic bleeding (P = 0.40) within 6-12 h of treatment in 100% of the cases, and restored blood coagulation (P = 0.87) within 6-24 h in 84.7% of patients, and within 48 h in all of them, in agreement with restoration of plasma fibrinogen concentration. Venom concentrations in serum dropped significantly (P < 0.001), to very low levels, 1 h after antivenom infusion. Nevertheless, eight patients (11.1%), four for each antivenom, presented recurrence of venom antigenaemia at different times, from 6 to 96 h, with clinical significance (recurrent coagulopathy) only in one group B patient (2.9%). Serum creatine kinase (CK) activity was increased, as a consequence of local myonecrosis. There was no significant difference (P = 0.51) in the incidence of early adverse reactions to antivenom administration (28.9% for patients of group A and 20.6% for patients of group B), most of the reactions being mild, mainly cutaneous. The most frequent complications were cellulitis (16.7%), abscess formation (5.6%), acute renal failure (8.3%), and compartmental syndrome (5.6%). In conclusion, IgG and F(ab')2 antivenoms, prepared by caprylic acid fractionation, presented similar efficacy and safety profiles for the treatment of B. asper envenomings in Colombia.

In this paper, the use of visible light communications (VLC) technologies for providing data networking for passengers during flight is explored. An uplink channel based on infrared is also studied. The potential capabilities of this optical access technique are examined.