970 resultados para Coração - Sons
Resumo:
The mineral brushite has been synthesised by mixing calcium ions and hydrogen phosphate anions to mimic the reactions in a Cave. The vibrational spectra of the synthesised brushite were compared with that of the natural Cave mineral. Bands attributable to the PO43- and HPO42- anions are observed. Brushite, both synthetic and natural, is characterised by an intense sharp band at 985 cm-1 with a shoulder at 1000 cm-1. Characteristic bending modes are observed in the 300 to 600 cm-1 region. The spectra of the synthesised brushite matches very well the spectrum of brushite from the Moorba Cave, Western Australia.
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Geelong, Victoria’s second city, has an AFL football club whose culture and identity is closely tied to the city itself. An analysis of its playing group for the colonial period demonstrates that this local tribalism began early. As football became professionalised towards the end of the nineteenth century, country Victoria lost power in relative terms to metropolitan Melbourne: for example, Ballarat’s three main clubs lost their senior status. But Geelong, with its one remaining senior club, prospered and was admitted to the VFL ranks in 1897. The Geelong players were the sons and nephews of the Western District squattocracy and so had access to networks of power and influence. Many attended the prestigious Geelong Grammar School and the worthy Geelong College (in surprisingly equal numbers). They pursued careers both on the land and in professional roles, and maintained the social connections they had built through the club and other local institutions. Despite their elite standing, however, they continued to be regarded by the supporter base as an embodiment of the city and a defence against the city’s Melbourne critics that Geelong was a mere ‘sleepy hollow’.
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With new photocatalysts of gold nanoparticles supported on zeolite supports (Au/zeolite), oxidation of benzyl alcohol and its derivatives into the corresponding aldehydes can proceed well with a high selectivity (99%) under visible light irradiation at ambient temperature. Au/zeolite photocatalysts were characterized by UV/Vis, XPS, TEM, XRD, EDS, BET, IR, and Raman techniques. The Surface Plasmon Resonance (SPR) effect of gold nanoparticles, the adsorption capability of zeolite supports, and the molecular polarities of aromatic alcohols were demonstrated to have an essential correlation with the photocatalytic performances. In addition, the effects of light intensity, wavelength range, and the role of molecular oxygen were investigated in detail. The kinetic study indicated that the visible light irradiation required much less apparent activation energy for photooxidation compared with thermal reaction. Based on the characterization data and the photocatalytic performances, we proposed a possible photooxidation mechanism.
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Homo-and heteronuclear meso,meso-(E)-ethene-1,2-diyl-linked diporphyrins have been prepared by the Suzuki coupling of porphyrinylboronates and iodovinylporphyrins. Combinations comprising 5,10,15-triphenylporphyrin (TriPP) on both ends of the ethene-1,2-diyl bridge M 210 (M 2=H 2/Ni, Ni 2, Ni/Zn, H 4, H 2Zn, Zn 2) and 5,15-bis(3,5-di-tert-butylphenyl)porphyrinato-nickel(II) on one end and H 2, Ni, and ZnTriPP on the other (M 211), enable the first studies of this class of compounds possessing intrinsic polarity. The compounds were characterized by electronic absorption and steady state emission spectra, 1H NMR spectra, and for the Ni 2 bis(TriPP) complex Ni 210, single crystal X-ray structure determination. The crystal structure shows ruffled distortions of the porphyrin rings, typical of Ni II porphyrins, and the (E)-C 2H 2 bridge makes a dihedral angle of 50° with the mean planes of the macrocycles. The result is a stepped parallel arrangement of the porphyrin rings. The dihedral angles in the solid state reflect the interplay of steric and electronic effects of the bridge on interporphyrin communication. The emission spectra in particular, suggest energy transfer across the bridge is fast in conformations in which the bridge is nearly coplanar with the rings. Comparisons of the fluorescence behaviour of H 410 and H 2Ni10 show strong quenching of the free base fluorescence when the complex is excited at the lower energy component of the Soret band, a feature associated in the literature with more planar conformations. TDDFT calculations on the gas-phase optimized geometry of Ni 210 reproduce the features of the experimental electronic absorption spectrum within 0.1 eV. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (TTY). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of −110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and TTY were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72 h post-treatment. WBC reduced TTY, by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.
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In comparison to our knowledge of the recycling of adhesion receptors and actin assembly, exactly how the cell controls its surface membrane to form a lamellipodium during migration is poorly understood. Here, we show the recycling endosome membrane is incorporated into the leading edge of a migrating cell to expand lamellipodia membrane. We have identified the SNARE complex that is necessary for fusion of the recycling endosome with the cell surface, as consisting of the R-SNARE VAMP3 on the recycling endosome partnering with the surface Q-SNARE Stx4/SNAP23, which was found to translocate and accumulate on the leading edge of migrating cells. Increasing VAMP3-mediated fusion of the recycling endosome with the surface increased membrane ruffling, while inhibition of VAMP3-mediated fusion showed that incorporation of the recycling endosome is necessary for efficient lamellipodia formation. At the same time, insertion of this recycling endosome membrane also delivers its cargo integrin α5β1 to the cell surface. The loss of this extra membrane for lamellipodia expansion and delivery of cargo in cells resulted in macrophages with a diminished capacity to effectively migrate. Thus, the recycling endosome membrane is incorporated into the leading edge and this aids expansion of the lamellipodia and simultaneously delivers integrins necessary for efficient cell migration.
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Background: The term ‘green health promotion’ is given to health promotion underpinned by the principles of ecological health and sustainability. Green health promotion is supported philosophically by global health promotion documents such as the Ottawa Charter for Health Promotion (1986) and the ecological public health movement. Green health promotion in schools aims to practice the principles of ecological health and sustainability. Methods: An extended literature review revealed a paucity of literature about green health promotion in schools across disciplines. Literature about nurses and health promotion in schools is generally found in nursing publications. Literature about ecological sustainability in schools is mostly found in teaching publications. Results: This paper explores the nexus between nursing and health promotion, and teachers and ecological sustainability. Collaborative partnerships between health and education do not capitalise on programs such as Health Promoting Schools and the School Based Youth Health Nurse Program in Queensland, Australia. The authors consider how collaborative partnerships between health and education in schools can work towards green health promotion. Conclusion: Nursing’s approach to health promotion and education’s approach to ecological sustainability need to be aligned to enhance green health promotion in schools and promote a new generation of ‘tree huggers and hippies’.
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Living mammals can be divided into three subclasses (monotremes, marsupials and placentals) and within these, about 27 orders. Final resolution of the relationships between the orders is only now being achieved with the increased availability of deoxyribonucleic acid (DNA) sequences. Highlights include the deep division of placental mammals into African (Afrotheria), South American (Xenarthra) and northern hemisphere (Boreoeutheria) super-orders, and the finding that the once considered primitive ‘Insectivora’ and ‘Edentata’ clades, in fact, have members distributed widely among these super-orders. Another surprise finding from DNA studies has been that whale origins lie among the even-toed ungulates (Artiodactyla). Our order, Primates is most closely related to the flying lemurs and next, the tree shrews. With the mammal phylogeny becoming well resolved, it is increasingly being used as a framework for inferring evolutionary and ecological processes, such as adaptive radiation.
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This study investigates the effect of well-defined poly(dimethylsiloxane)-poly(ethylene glycol) (PDMS-PEG) ABA linear block co-oligomers on the proliferation of human dermal fibroblasts. The co-oligomers assessed ranged in molecular weight (MW) from 1335 to 5208 Da and hydrophilic-lipophilic balance (HLB) from 5.9 to 16.6 by varying the number of both PDMS and PEG units. In general, it was found that co-oligomers of low MW or intermediate hydrophilicity significantly reduced fibroblast proliferation. A linear relationship between down-regulation of fibroblast proliferation, and the ratio HLB/MW was observed at concentrations of 0.1 and 1.0 wt % of the oligomers. This enabled the structures with highest efficiency to be determined. These results suggest the possible use of the PEG-PDMS-PEG block co-oligomers as an alternative to silicone gels for hypertrophic scar remediation.
A tan in a test tube -in vitro models for investigating ultraviolet radiation-induced damage in skin
Resumo:
Presently, global rates of skin cancers induced by ultraviolet radiation (UVR) exposure are on the rise. In view of this, current knowledge gaps in the biology of photocarcinogenesis and skin cancer progression urgently need to be addressed. One factor that has limited skin cancer research has been the need for a reproducible and physiologically-relevant model able to represent the complexity of human skin. This review outlines the main currently-used in vitro models of UVR-induced skin damage. This includes the use of conventional two-dimensional cell culture techniques and the major animal models that have been employed in photobiology and photocarcinogenesis research. Additionally, the progression towards the use of cultured skin explants and tissue-engineered skin constructs, and their utility as models of native skin's responses to UVR are described. The inherent advantages and disadvantages of these in vitro systems are also discussed.
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The integration of unmanned aircraft into civil airspace is a complex issue. One key question is whether unmanned aircraft can operate just as safely as their manned counterparts. The absence of a human pilot in unmanned aircraft automatically points to a deficiency that is the lack of an inherent see-and-avoid capability. To date, regulators have mandated that an “equivalent level of safety” be demonstrated before UAVs are permitted to routinely operate in civil airspace. This chapter proposes techniques, methods, and hardware integrations that describe a “sense-and-avoid” system designed to address the lack of a see-and-avoid capability in UAVs.
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Critical-sized bone defect regeneration is a remaining clinical concern. Numerous scaffold-based strategies are currently being investigated to enable in vivo bone defect healing. However, a deeper understanding of how a scaffold influences the tissue formation process and how this compares to endogenous bone formation or to regular fracture healing is missing. It is hypothesized that the porous scaffold architecture can serve as a guiding substrate to enable the formation of a structured fibrous network as a prerequirement for later bone formation. An ovine, tibial, 30-mm critical-sized defect is used as a model system to better understand the effect of the scaffold architecture on cell organization, fibrous tissue, and mineralized tissue formation mechanisms in vivo. Tissue regeneration patterns within two geometrically distinct macroscopic regions of a specific scaffold design, the scaffold wall and the endosteal cavity, are compared with tissue formation in an empty defect (negative control) and with cortical bone (positive control). Histology, backscattered electron imaging, scanning small-angle X-ray scattering, and nanoindentation are used to assess the morphology of fibrous and mineralized tissue, to measure the average mineral particle thickness and the degree of alignment, and to map the local elastic indentation modulus. The scaffold proves to function as a guiding substrate to the tissue formation process. It enables the arrangement of a structured fibrous tissue across the entire defect, which acts as a secondary supporting network for cells. Mineralization can then initiate along the fibrous network, resulting in bone ingrowth into a critical-sized defect, although not in complete bridging of the defect. The fibrous network morphology, which in turn is guided by the scaffold architecture, influences the microstructure of the newly formed bone. These results allow a deeper understanding of the mode of mineral tissue formation and the way this is influenced by the scaffold architecture. Copyright © 2012 American Society for Bone and Mineral Research.
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The nitrile imine-mediated tetrazole-ene cycloaddition reaction (NITEC) is introduced as a powerful and versatile conjugation tool to covalently ligate macromolecules onto variable (bio)surfaces. The NITEC approach is initiated by UV irradiation and proceeds rapidly at ambient temperature yielding a highly fluorescent linkage. Initially, the formation of block copolymers by the NITEC methodology is studied to evidence its efficacy as a macromolecular conjugation tool. The grafting of polymers onto inorganic (silicon) and bioorganic (cellulose) surfaces is subsequently carried out employing the optimized reaction conditions obtained from the macromolecular ligation experiments and evidenced by surface characterization techniques, including X-ray photoelectron spectroscopy and FT-IR microscopy. In addition, the patterned immobilization of variable polymer chains onto profluorescent cellulose is achieved through a simple masking process during the irradiation. Photoinduced nitrile imine-alkene 1,3-dipolar cycloaddition (NITEC) is employed to covalently bind well-defined polymers onto silicon oxide or cellulose. A diaryl tetrazole-functionalized molecule is grafted via silanization or amidification, respectively. Under UV light, a reactive nitrile imine rapidly forms and reacts with maleimide-functionalized polymers yielding a fluorescent linkage. Via a masking method, polymeric fluorescent patterns are achieved.
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With the continued development of renewable energy generation technologies and increasing pressure to combat the global effects of greenhouse warming, plug-in hybrid electric vehicles (PHEVs) have received worldwide attention, finding applications in North America and Europe. When a large number of PHEVs are introduced into a power system, there will be extensive impacts on power system planning and operation, as well as on electricity market development. It is therefore necessary to properly control PHEV charging and discharging behaviors. Given this background, a new unit commitment model and its solution method that takes into account the optimal PHEV charging and discharging controls is presented in this paper. A 10-unit and 24-hour unit commitment (UC) problem is employed to demonstrate the feasibility and efficiency of the developed method, and the impacts of the wide applications of PHEVs on the operating costs and the emission of the power system are studied. Case studies are also carried out to investigate the impacts of different PHEV penetration levels and different PHEV charging modes on the results of the UC problem. A 100-unit system is employed for further analysis on the impacts of PHEVs on the UC problem in a larger system application. Simulation results demonstrate that the employment of optimized PHEV charging and discharging modes is very helpful for smoothing the load curve profile and enhancing the ability of the power system to accommodate more PHEVs. Furthermore, an optimal Vehicle to Grid (V2G) discharging control provides economic and efficient backups and spinning reserves for the secure and economic operation of the power system
Resumo:
Red light cameras (RLC) have been used to reduce right-angle collisions at signalized intersections. However, the effect of RLCs on motorcycle crashes has not been well investigated. The objective of this study is to evaluate the effectiveness of RLCs on motorcycle safety in Singapore. This is done by comparing their exposure, proneness of at-fault right-angle crashes as well as the resulting right-angle collisions at RLC with those at non-RLC sites. Estimating the crash vulnerability from not-at-fault crash involvements, the study shows that with a RLC, the relative crash vulnerability or crash-involved exposure of motorcycles at right-angle crashes is reduced. Furthermore, field investigation of motorcycle maneuvers reveal that at non-RLC arms, motorcyclists usually queue beyond the stop-line, facilitating an earlier discharge and hence become more exposed to the conflicting stream. However at arms with a RLC, motorcyclists are more restrained to avoid activating the RLC and hence become less exposed to conflicting traffic during the initial period of the green. The study also shows that in right-angle collisions, the proneness of at-fault crashes of motorcycles is lowest among all vehicle types. Hence motorcycles are more likely to be victims than the responsible parties in right-angle crashes. RLCs have also been found to be very effective in reducing at-fault crash involvements of other vehicle types which may implicate exposed motorcycles in the conflicting stream. Taking all these into account, the presence of RLCs should significantly reduce the vulnerability of motorcycles at signalized intersections.