495 resultados para hyperpolarisierte Gase, He-3, MRT, Lunge, Applikator
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The Marquis de Sade was declared, “the fist commandment of art is ‘never to bore,’” and perhaps no other artist of his generation has embodied this sentiment more than Guillermo Gómez- Peña, the Mexican-born performance artist and cultural theorist living in San Francisco. Since the early 1980s Gómez-Peña, along with his performance troupe La Pocha Nostra, have been engaged in “reverse anthropology” staging “postcolonial” performances that foreground race and intervene in our cultural fears and desires by focusing on our obsession with the exotic. He deftly navigates the “post-multicultural” world – accelerated by globalization and nation branding – by using elaborate performative and interactive elements that expose (to the audience) their deeply embedded cultural stereotypes and desires for the other.
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Abnormal “polymer-in-salt” conduction behavior is observed in a solid electrolyte composed of lithium iodide (LiI) and 3-hydroxypropionitrile (HPN). Based on comprehensive investigations by X-ray diffraction (XRD) and Raman and infrared spectroscopy, this abnormal conduction behavior is attributed to the formation of new ionic associates [Lim +In−]· · ·N C (m> n) and the reinforced hydrogen bonding of I· · ·HO in the electrolyte at high LiI concentrations.
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Purpose To develop a novel 3-D cell culture model with the view to studying the pathomechanisms underlying the development of age-related macular degeneration (AMD). Our central hypothesis is that the silk structural protein fibroin used in conjunction with cultured human cells can be used to mimic the structural relationships between the RPE and choriocapillaris in health and disease. Methods Co-cultures of human RPE cells (ARPE-19 cells grown in Miller’s medium) and microvascular endothelial cells (HMEC-1 cells grown in endothelial culture medium) were established on opposing sides of a synthetic Bruch’s membrane (3 microns thick) constructed from B mori silk fibroin. Cell attachment was facilitated by pre-coating the fibroin membrane with vitronectin (for ARPE-19 cells) and gelatin (for HMEC-1 cells) respectively. The effects of tropoelastin on attachment of ARPE-19 cells was also examined. Barrier function was examined by measurement of trans-epithelial resistance (TER) using a voltohmmeter (EVOM-2). The phagocytic activity of the synthetic RPE was tested using vitronectin-coated microspheres (2 micron diameter FluoSpheres). In some cultures, membrane defects were created by puncturing within a 24 G needle. The architecture of the synthetic tissue before and after wounding was examined by confocal microscopy after staining for ZO-1 and F-actin. Results The RPE layer of the 3D model developed a cobblestoned morphology (validated by staining for ZO-1 and F-actin), displayed barrier function (validated by measurement of TER) and demonstrated cytoplasmic uptake of vitronectin-coated microspheres. Attachment of ARPE-19 cells to fibroin was unaffected by tropoelastin. Microvascular endothelial cells attached well to the gelatin-coated surface of the fibroin membrane and remained physically separated from the overlaying RPE layer. The fibroin membranes were amenable to puncturing without collapse thus providing the opportunity to study transmembrane migration of the endothelial cells. Conclusions Synthetic Bruch’s membranes constructed from silk fibroin, vitronectin and gelatin, support the co-cultivation of RPE cells and microvascular endothelial cells. The resulting RPE layer displays functions similar to that of native RPE and the entire tri-layered structure displays potential to be used as an in vitro model of choroidal neovascularization.
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Problem crying in the first few months of life is both common and complex, arising out of multiple interacting and co-evolving factors. Parents whose babies cry and fuss a lot receive conflicting advice as they seek help from multiple health providers and emergency departments, and may be admitted into tertiary residential services. Conflicting advice is costly, and arises out of discipline-specific interpretations of evidence. An integrated, interdisciplinary primary care intervention (‘The Possums Approach’) for cry-fuss problems in the first months of life was developed from available peer-reviewed evidence. This study reports on preliminary evaluation of delivery of the intervention. A total of 20 mothers who had crying babies under 16 weeks of age (average age 6.15 weeks) completed questionnaires, including the Crying Patterns Questionnaire and the Edinburgh Postnatal Depression Scale, before and 3-4 weeks after their first consultation with trained primary care practitioners. Preliminary evaluation is promising. The Crying Patterns Questionnaire showed a significant decrease in crying and fussing duration, by 1 h in the evening (P = 0.001) and 30 min at night (P = 0.009). The median total amount of crying and fussing in a 24-h period was reduced from 6.12 to 3 h. The Edinburgh Postnatal Depression Scale showed a significant improvement in depressive symptoms, with the median score decreasing from 11 to 6 (P = 0.005). These findings are corroborated by an analysis of results for the subset of 16 participants whose babies were under 12 weeks of age (average age 4.71 weeks). These preliminary results demonstrate significantly decreased infant crying in the evening and during the night and improved maternal mood, validating an innovative interdisciplinary clinical intervention for cry-fuss problems in the first few months of life. This intervention, delivered by trained health professionals, has the potential to mitigate the costly problem of health professionals giving discipline-specific and conflicting advice post-birth.
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The objective of this work is to analyze ludlamite (Fe,Mn,Mg)3(PO4)2⋅4H2O from Boa Vista mine, Galiléia, Brazil and to assess the molecular structure of the mineral. The phosphate mineral ludlamite has been characterized by EMP-WDS, Raman and infrared spectroscopic measurements. The mineral is shown to be a ferrous phosphate with some minor substitution of Mg and Mn. Raman bands at 917 and 950 cm−1 are assigned to the symmetric stretching mode of and units. Raman bands at 548, 564, 599 and 634 cm−1 are assigned to the ν4 bending modes. Raman bands at 2605, 2730, 2896 and 3190 cm−1 and infrared bands at 2623, 2838, 3136 and 3185 cm−1 are attributed to water stretching vibrations. By using a Libowitzky empirical function, hydrogen bond distances are calculated from the OH stretching wavenumbers. Strong hydrogen bonds in the structure of ludlamite are observed as determined by their hydrogen bond distances. The application of infrared and Raman spectroscopy to the study of ludlamite enables the molecular structure of the pegmatite mineral ludlamite to be assessed.
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Papagoite is a silicate mineral named after an American Indian tribe and was used as a healing mineral. Papagoite CaCuAlSi2O6(OH)3 is a hydroxy mixed anion compound with both silicate and hydroxyl anions in the formula. The structural characterization of the mineral papagoite remains incomplete. Papagoite is a four-membered ring silicate with Cu2+ in square planar coordination. The intense sharp Raman band at 1053 cm−1 is assigned to the ν1 (A 1g) symmetric stretching vibration of the SiO4 units. The splitting of the ν3 vibrational mode offers support to the concept that the SiO4 tetrahedron in papagoite is strongly distorted. A very intense Raman band observed at 630 cm−1 with a shoulder at 644 cm−1 is assigned to the ν4 vibrational modes. Intense Raman bands at 419 and 460 cm−1 are attributed to the ν2 bending modes. Intense Raman bands at 3545 and 3573 cm−1 are assigned to the stretching vibrations of the OH units. Low-intensity Raman bands at 3368 and 3453 cm−1 are assigned to water stretching modes. It is suggested that the formula of papagoite is more likely to be CaCuAlSi2O6(OH)3 · xH2O. Hence, vibrational spectroscopy has been used to characterize the molecular structure of papagoite.
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The objective of this research was to investigate the effects of driving conditions and suspension parameters on dynamic load-sharing of longitudinal-connected air suspensions of a tri-axle semi-trailer. A novel nonlinear model of a multi-axle semi-trailer with longitudinal-connected air suspension was formulated based on fluid mechanics and thermodynamics and was validated through test results. The effects of driving conditions and suspension parameters on dynamic load-sharing and road-friendliness of the semi-trailer were analyzed. Simulation results indicate that the road-friendliness metric-DLC (dynamic load coefficient) is not always in accordance with the load-sharing metric-DLSC (dynamic load-sharing coefficient). The effect of employing larger air lines and connectors on the DLSC optimization ratio gives varying results as road roughness increases and as driving speed increases. When the vehicle load reduces, or the static pressure increases, the DLSC optimization ratio declines monotonically. The results also indicate that if the air line diameter is always assumed to be larger than the connector diameter, the influence of air line diameter on load-sharing is more significant than that of the connector.
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In the structure of the title compound, [Mg(C7H3N2O6)2(H2O)4] . 4H2O), the slightly distorted octahedral MgO6 coordination polyhedron comprises two trans-related carboxyl O-atom donors from mononodentate 3,5-dinitrobenzoate ligands, and four water molecules. The coordinated water molecules and the four water molecules of solvation give both intra- and inter-unit O-H...O hydrogen-bonding interactions with carboxyl, water and nitro O-atom acceptors, giving a three-dimensional structure.
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Vibrational spectroscopy enables subtle details of the molecular structure of cyrilovite to be determined. Single crystals of a pure phase from a Brazilian pegmatite were used. Cyrilovite is the Fe3+ member of the wardite group. The infrared and Raman spectroscopy were applied to compare the structure of cyrilovite with that of wardite. The Raman spectrum of cyrilovite in the 800–1400 cm−1 spectral range shows two intense bands at 992 and 1055 cm−1 assigned to the ν1View the MathML source symmetric stretching vibrations. A series of low intensity bands at 1105, 1136, 1177 and 1184 cm−1 are assigned to the ν3View the MathML source antisymmetric stretching modes. The infrared spectrum of cyrilovite in the 500–1300 cm−1 shows much greater complexity than the Raman spectrum. Strong infrared bands are found at 970 and 1007 cm−1 and are attributed to the ν1View the MathML source symmetric stretching mode. Raman bands are observed at 612 and 631 cm−1 and are assigned to the ν4 out of plane bending modes of the View the MathML source unit. In the 2600–3800 cm−1 spectral range, intense Raman bands for cyrilovite are found at 3328 and 3452 cm−1 with a broad shoulder at 3194 cm−1 and are assigned to OH stretching vibrations. Sharp infrared bands are observed at 3485 and 3538 cm−1. Raman spectroscopy complimented with infrared spectroscopy has enabled the structure of cyrilovite to be ascertained and compared with that of wardite.
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We have analyzed a frondelite mineral sample from the Cigana mine, located in the municipality of Conselheiro Pena, a well-known pegmatite in Brazil. In the Cigana pegmatite, secondary phosphates, namely eosphorite, fairfieldite, fluorapatite, frondelite, gormanite, hureaulite, lithiophilite, reddingite and vivianite are common minerals in miarolitic cavities and in massive blocks after triphylite. The chemical formula was determined as (Mn0.68, Fe0.32)(Fe3+)3,72(PO4)3.17(OH)4.99. The structure of the mineral was assessed using vibrational spectroscopy. Bands attributed to the stretching and bending modes of PO4 3- and HOPO3 3- units were identified. The observation of multiple bands supports the concept of symmetry reduction of the phosphate anion in the frondelite structure. Sharp Raman and infrared bands at 3581 cm−1 is assigned to the OH stretching vibration. Broad Raman bands at 3063, 3529 and 3365 cm−1 are attributed to water stretching vibrational modes.
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We sought to determine the impact of electrospinning parameters on a trustworthy criterion that could evidently improve the maximum applicability of fibrous scaffolds for tissue regeneration. We used an image analysis technique to elucidate the web permeability index (WPI) by modeling the formation of electrospun scaffolds. Poly(3-hydroxybutyrate) (P3HB) scaffolds were fabricated according to predetermined conditions of levels in a Taguchi orthogonal design. The material parameters were the polymer concentration, conductivity, and volatility of the solution. The processing parameters were the applied voltage and nozzle-to-collector distance. With a law to monitor the WPI values when the polymer concentration or the applied voltage was increased, the pore interconnectivity was decreased. The quality of the jet instability altered the pore numbers, areas, and other structural characteristics, all of which determined the scaffold porosity and aperture interconnectivity. An initial drastic increase was observed in the WPI values because of the chain entanglement phenomenon above a 6 wt % P3HB content. Although the solution mixture significantly (p < 0.05) changed the scaffold architectural characteristics as a function of the solution viscosity and surface tension, it had a minor impact on the WPI values. The solution mixture gained the third place of significance, and the distance was approved as the least important factor.
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The well-known power system stabilizer (PSS) is used to generate supplementary control signals for the excitation system of a generator so as to damp low frequency oscillations in the power system concerned. Up to now, various kinds of PSS design methods have been proposed and some of them applied in actual power systems with different degrees. Given this background, the small-disturbance eigenvalue analysis and large-disturbance dynamic simulations in the time domain are carried out to evaluate the performances of four different PSS design methods, including the Conventional PSS (CPSS), Single-Neuron PSS (SNPSS), Adaptive PSS (APSS) and Multi-band PSS (MBPSS). To make the comparisons equitable, the parameters of the four kinds of PSSs are all determined by the steepest descent method. Finally, an 8-unit 24-bus power system is employed to demonstrate the performances of the four kinds of PSSs by the well-established eigenvalue analysis as well as numerous digital simulations, and some useful conclusions obtained.
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This note examines the productive efficiency of 62 starting guards during the 2011/12 National Basketball Association (NBA) season. This period coincides with the phenomenal and largely unanticipated performance of New York Knicks’ starting point guard Jeremy Lin and the attendant public and media hype known as Linsanity. We employ a data envelopment analysis (DEA) approach that includes allowance for an undesirable output, here turnovers per game, with the desirable outputs of points, rebounds, assists, steals and blocks per game and an input of minutes per game. The results indicate that depending upon the specification, between 29% and 42% of NBA guards are fully efficient, including Jeremy Lin, with a mean inefficiency of 3.7% and 19.2%. However, while Jeremy Lin is technically efficient, he seldom serves as a benchmark for inefficient players, at least when compared with established players such as Chris Paul and Dwayne Wade. This suggests the uniqueness of Jeremy Lin's productive solution and may explain why his unique style of play, encompassing individual brilliance, unselfish play and team leadership, is of such broad public appeal.
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The last 50 years have produced multiple changes in our understanding of the place of paid and unpaid work in women’s lives. A growing theoretical, research and practical literature attests to the attention being directed to the a broader understanding of women’s working lives. It is more than thirty years since the groundbreaking paper by Fitzgerald and Crites’ (1980) on the career psychology of women. Prior to that time women’s careers were seen as primarily home based or “in relation to” men’s careers. In 1975 Osipow had commented on the lack of usefulness of traditional theories of career behaviour for women in that several basic assumptions on which they were founded were not relevant. For example, traditional career theory is based on the assumption that an array of career choices is available to all individuals, who are in turn motivated to pursue their personal interests in making certain choices. A comment on the state of vocational psychology in relation to class made by Tyler in 1967 highlights the inadequacy of application to women: - "much of what we know about the stages through which an individual passes as he prepares to find his place in the world of work might appropriately be labelled the vocational development of white middle class males" (p. 62; original italics). Gilligan's (1979) classic article entitled "woman's place in man's life cycle" emphasised the restriction of many theories of psychology in understanding women's lives as they implicitly adopted male as norm and failed to account for the unique social and family situation of women and the related demands on them...
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Biomechanics involves research and analysis of the mechanisms of living organisms. This can be conducted on multiple levels and represents a continuum from the molecular, wherein biomaterials such as collagen and elastin are considered, to the tissue, organ and whole body level. Some simple applications of Newtonian mechanics can supply correct approximations on each level, but precise details demand the use of continuum mechanics. Sport biomechanics uses the scientific methods of mechanics to study the effects of forces on the sports performer and considers aspects of the behaviour of sports implements, equipment, footwear and surfaces. There are two main aims of sport biomechanics, that is, the reduction of injury and the improvement of performance (Bartlett, 1999). Aristotle (384-322 BC) wrote the first book on biomechanics, De Motu Animalium, translated as On the Movement of Animals. He saw animals' bodies as mechanical systems, but also pursued questions that might explain the physiological difference between imagining the performance of an action and actually doing it. Some simple examples of biomechanics research include the investigation of the forces that act on limbs, the aerodynamics of animals in flight, the hydrodynamics of objects moving through water and locomotion in general across all forms of life, from individual cells to whole organisms...