125 research outputs found

    Dielectric Resonator Nanoantenna Coupled To Metallic Coplanar Waveguide

    Get PDF
    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A proposal about a dielectric resonator nanoantenna applied to couple optical beams to a surface plasmon coplanar waveguide (SP CPW), and vice versa, was theoretically investigated. The effects of this device operating in optical frequencies were studied, taking into account the central frequency of the conventional optical communication spectrum (C-band). Numerical results show that this proposal is interesting in that it couples an optical beam with an SP CPW with a good reflection coefficient, gain, and broadside radiation pattern.71Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2010/18857-7, 2013/03947-9

    Wireless link evaluation of a dielectric resonator nanoantenna

    Get PDF
    Optical antennas/nanoantennas are optical elements that have gained highlight in this decade and have potential application in several branches of photonics/plasmonics, such as, optical sensors, lasers, solid state lighting, photovoltaics, microscopy, etc. Additionally, the dipole nanoantennas have been the antennas elements mostly studied in proposals for those applications and, in special, for free-space communication based on plasmonic circuits. Here we report some advantages of dielectric resonator nanoantennas (DRNAs) as elements for coupling light to plasmonic-based circuits. Fundamental antenna parameters such as reflection coefficient, gain, efficiency, among others, are evaluated and its advantages are highlighted for nanophotonics applications. A study about an optical link for circuits based on metal-dielectric-metal-dielectric (MDMD) nanostrip waveguides operating at the central wavelength of λ0 = 1.55 μm is evaluated. We studied the coupling of near- and far-fields of a DRNA matched to an MDMD nanostrip waveguide. The results show the advantage of it as an element for optical coupling from/to free-space as well as to establish a wireless optical link for inter-chip communication10924SPIE OPTO - Optical Interconnects XI

    Upregulation of the voltage-gated sodium channel beta2 subunit in neuropathic pain models: characterization of expression in injured and non-injured primary sensory neurons

    Get PDF
    The development of abnormal primary sensory neuron excitability and neuropathic pain symptoms after peripheral nerve injury is associated with altered expression of voltage-gated sodium channels (VGSCs) and a modification of sodium currents. To investigate whether the beta2 subunit of VGSCs participates in the generation of neuropathic pain, we used the spared nerve injury (SNI) model in rats to examine beta2 subunit expression in selectively injured (tibial and common peroneal nerves) and uninjured (sural nerve) afferents. Three days after SNI, immunohistochemistry and Western blot analysis reveal an increase in the beta2 subunit in both the cell body and peripheral axons of injured neurons. The increase persists for >4 weeks, although beta2 subunit mRNA measured by real-time reverse transcription-PCR and in situ hybridization remains unchanged. Although injured neurons show the most marked upregulation,beta2 subunit expression is also increased in neighboring non-injured neurons and a similar pattern of changes appears in the spinal nerve ligation model of neuropathic pain. That increased beta2 subunit expression in sensory neurons after nerve injury is functionally significant, as demonstrated by our finding that the development of mechanical allodynia-like behavior in the SNI model is attenuated in beta2 subunit null mutant mice. Through its role in regulating the density of mature VGSC complexes in the plasma membrane and modulating channel gating, the beta2 subunit may play a key role in the development of ectopic activity in injured and non-injured sensory afferents and, thereby, neuropathic pain

    Adolescent dietary manipulations differentially affect gut microbiota composition and amygdala neuroimmune gene expression in male mice in adulthood

    Get PDF
    peer-reviewedAdolescence is a critical developmental period that is characterised by growth spurts and specific neurobiological, neuroimmune and behavioural changes. In tandem the gut microbiota, which is a key player in the regulation of health and disease, is shaped during this time period. Diet is one of the most important regulators of microbiota composition. Thus, we hypothesised that dietary disturbances of the microbiota during this critical time window result in long-lasting changes in immunity, brain and behaviour. C57BL/6 male mice were exposed to either high fat diet or cafeteria diet during the adolescent period from postnatal day 28 to 49 and were tested for anxiety-related and social behaviour in adulthood. Our results show long-lasting effects of dietary interventions during the adolescent period on microbiota composition and the expression of genes related to neuroinflammation or neurotransmission. Interestingly, changes in myelination-related gene expression in the prefrontal cortex following high fat diet exposure were also observed. However, these effects did not translate into overt behavioural changes in adulthood. Taken together, these data highlight the importance of diet-microbiota interactions during the adolescent period in shaping specific outputs of the microbiota-gut-brain axis in later life.Science Foundation Irelan

    Snow White Is Missing: An Interactive Locative Story for Dementia Patients

    Get PDF
    With the increasing prevalence of powerful mobile technology, interactive entertainment is also becoming increasingly mobile. This can also be said for a range of applications including those pertaining to mental and physical health which are also looking to take advantage of the increase in mobile technology to create digital interventions and other treatment based software for mobile devices that can benefit from the mobile deliver form. In this paper we propose a new form of serious game in this vein: therapeutic locative interactive fiction. These are interactive story experiences, read while on the move, that respond to the readers environment and location context, and have therapeutic value. The locative nature of these stories enables therapeutic activities connected with out door spaces, and allows for content to enrich users, the readers of locational context. We present a demonstration of this concept through our own therapeutic locative interactive narrative: Snow White is Missing, and detail both its design from an interactive narrative and therapeutic activity perspectives

    Enduring neurobehavioral effects induced by microbiota depletion during the adolescent period

    Get PDF
    Peer ReviewedThe gut microbiota is an essential regulator of many aspects of host physiology. Disruption of gut microbial communities affects gut-brain communication which ultimately can manifest as changes in brain function and behaviour. Transient changes in gut microbial composition can be induced by various intrinsic and extrinsic factors, however, it is possible that enduring shifts in the microbiota composition can be achieved by perturbation at a timepoint when the gut microbiota has not fully matured or is generally unstable, such as during early life or ageing. In this study, we investigated the effects of 3-week microbiota depletion with antibiotic treatment during the adolescent period and in adulthood. Following a washout period to restore the gut microbiota, behavioural and molecular hallmarks of gut-brain communication were investigated. Our data revealed that transient microbiota depletion had long-lasting effects on microbiota composition and increased anxiety-like behaviour in mice exposed to antibiotic treatment during adolescence but not in adulthood. Similarly, gene expression in the amygdala was more severely affected in mice treated during adolescence. Taken together these data highlight the vulnerability of the gut microbiota during the critical adolescent period and the long-lasting impact manipulations of the microbiota can have on gene expression and behaviour in adulthood.Science Foundation Irelan

    Ultrastructural changes of the intracellular surfactant pool in a rat model of lung transplantation-related events

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Ischemia/reperfusion (I/R) injury, involved in primary graft dysfunction following lung transplantation, leads to inactivation of intra-alveolar surfactant which facilitates injury of the blood-air barrier. The alveolar epithelial type II cells (AE2 cells) synthesize, store and secrete surfactant; thus, an intracellular surfactant pool stored in lamellar bodies (Lb) can be distinguished from the intra-alveolar surfactant pool. The aim of this study was to investigate ultrastructural alterations of the intracellular surfactant pool in a model, mimicking transplantation-related procedures including flush perfusion, cold ischemia and reperfusion combined with mechanical ventilation.</p> <p>Methods</p> <p>Using design-based stereology at the light and electron microscopic level, number, surface area and mean volume of AE2 cells as well as number, size and total volume of Lb were determined in a group subjected to transplantation-related procedures including both I/R injury and mechanical ventilation (I/R group) and a control group.</p> <p>Results</p> <p>After I/R injury, the mean number of Lb per AE2 cell was significantly reduced compared to the control group, accompanied by a significant increase in the luminal surface area per AE2 cell in the I/R group. This increase in the luminal surface area correlated with the decrease in surface area of Lb per AE2. The number-weighted mean volume of Lb in the I/R group showed a tendency to increase.</p> <p>Conclusion</p> <p>We suggest that in this animal model the reduction of the number of Lb per AE2 cell is most likely due to stimulated exocytosis of Lb into the alveolar space. The loss of Lb is partly compensated by an increased size of Lb thus maintaining total volume of Lb per AE2 cell and lung. This mechanism counteracts at least in part the inactivation of the intra-alveolar surfactant.</p

    Activation of N-heterocyclic carbenes by {BeH<sub>2</sub>} and {Be(H)(Me)} fragments

    Get PDF
    A stable three-coordinate dimethylberyllium species coordinated by the 1,3-bis­(2,4,6-trimethylphenyl)­imidazol-2-ylidene (IMes) ligand is readily converted to the corresponding methylhydrido derivative through metathetical reaction with phenylsilane. Attempts to synthesize the corresponding molecular dihydrides are, however, unsuccessful and result in ring opening of an IMes ligand through hydride transfer to the donor carbon atom and the consequent formation of a heterocyclic beryllium organoamide. In agreement with previous calculations, we suggest that this process occurs via a Schlenk-type equilibration process and formation of a four-coordinate bis-NHC beryllium dihydride. These species are not observed, however, as the steric pressure exerted by coordination of the two sterically demanding IMes ligands is sufficient to induce hydride transfer. The latter deduction is supported by the observation that a similar ring-opened product, but derived from methyl and hydride transfer, is available through the introduction of a further equivalent of IMes to the isolated beryllium methyl hydride species. In the latter case the ring-opening process is more facile, which we ascribe to the increased steric pressure achieved upon the formation of four-coordinate beryllium. In a further striking reaction under more forcing thermal conditions, the carbene carbon center of an IMes ligand is observed to be completely eliminated with selective formation of a three-coordinate diamidoberyllium species

    Knowledge of Glasgow coma scale by air-rescue physicians

    Get PDF
    OBJECTIVE: To assess the theoretical and practical knowledge of the Glasgow Coma Scale (GCS) by trained Air-rescue physicians in Switzerland. METHODS: Prospective anonymous observational study with a specially designed questionnaire. General knowledge of the GCS and its use in a clinical case were assessed. RESULTS: From 130 questionnaires send out, 103 were returned (response rate of 79.2%) and analyzed. Theoretical knowledge of the GCS was consistent for registrars, fellows, consultants and private practitioners active in physician-staffed helicopters. The clinical case was wrongly scored by 38 participants (36.9%). Wrong evaluation of the motor component occurred in 28 questionnaires (27.2%), and 19 errors were made for the verbal score (18.5%). Errors were made most frequently by registrars (47.5%, p = 0.09), followed by fellows (31.6%, p = 0.67) and private practitioners (18.4%, p = 1.00). Consultants made significantly less errors than the rest of the participating physicians (0%, p < 0.05). No statistically significant differences were shown between anesthetists, general practitioners, internal medicine trainees or others. CONCLUSION: Although the theoretical knowledge of the GCS by out-of-hospital physicians is correct, significant errors were made in scoring a clinical case. Less experienced physicians had a higher rate of errors. Further emphasis on teaching the GCS is mandatory

    High-resolution and low-loss all-fiber spectral filters based on biconic tapers

    No full text
    A family of narrowband spectral filters based on biconic fiber tapers is investigated. These filters were made of highly-depressed-cladding single-mode fibers by a heat-and-pulling process, and using a cylindrical-tube graphite heater. The evolution of the taper profiles during the pulling of different elongations was modeled by a coupled system of partial differential equations governing the mass and axial momentum conservation. The optical responses were modeled by using the mode coupling theory. Theoretical results, ranging from prediction of the taper profiles to optical responses of these filters-transmission losses, free spectral range, and isolation-show strong accordance with experimental ones352453815390CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ300594/2017-
    corecore