236 research outputs found

    Liquid crystal hyperbolic metamaterial for wide-angle negative-positive refraction and reflection

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    We show that nanosphere dispersed liquid crystal (NDLC) metamaterial can be characterized in near IR spectral region as an indefinite medium whose real parts of effective ordinary and extraordinary permittivities are opposite in signs. Based on this fact we design a novel electrooptic effect: external electric field driven switch between normal refraction, negative refraction and reflection of TM incident electromagnetic wave from the boundary vacuum/NDLC. A detailed analysis of its functionality is given based on effective medium theory combined with a study of negative refraction in anisotropic metamaterials, and Finite Elements simulations

    A unified potential drop calibration function for common crack growth specimens

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    Calibration functions, used to determine crack extension from potential drop measurements, are not readily available for many common crack growth specimen types. This restricts testing to a limited number of specimen types, typically resulting in overly conservative material properties being used in residual life assessments. This paper presents a unified calibration function which can be applied to all common crack growth specimen types, mitigating this problem and avoiding the significant costs associated with the current conservative approach. Using finite element analysis, it has been demonstrated that Johnson’s calibration function can be applied to the seven most common crack growth specimen types: C(T), SEN(T), SEN(B), M(T), DEN(T), CS(T) and DC(T). A parametric study has been used to determine the optimum configuration of electrical current inputs and PD probes. Using the suggested configurations, the error in the measurement of crack extension is <6% for all specimen types, which is relatively small compared to other sources of error commonly associated with the potential drop technique

    Effect of dielectric medium anisotropy on the polarization degree of emission from a single quantum dash

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    This research was supported by the Polish Ministry of Science and Higher Education/the National Science Center Grant No. 2011/02/A/ST3/00152. The experiments have partially been performed within the laboratory infrastructure financed by the Polish Ministry of Science and Higher Education Grant No. 6167/IA/119/2012.Excitonic emission from single InAs/InGaAlAs/InP quantum dashes has been investigated in the context of degree of linear polarization by post-growth modification of its surrounding dielectric medium. We present optical spectroscopy measurements on a symmetric squared pedestal structures (mesas), and asymmetric rectangular ones oriented parallel or perpendicular to the main in-plane axis of the dashes [1-10]. Polarization resolved microphotoluminescence shows a significant quantitative modification of the degree of linear polarization value from -20% up to 70%. These results have been confronted with calculations of the coupling between the exciton transition dipole moment and electromagnetic field distributed in the vicinity of a quantum dash inside a processed mesa.Postprin

    Complete diagrammatics of the single ring theorem

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    Using diagrammatic techniques, we provide explicit functional relations between the cumulant generating functions for the biunitarily invariant ensembles in the limit of large size of matrices. The formalism allows to map two distinct areas of free random variables: Hermitian positive definite operators and non-normal R-diagonal operators. We also rederive the Haagerup-Larsen theorem and show how its recent extension to the eigenvector correlation function appears naturally within this approach.Comment: 18 pages, 6 figures, version accepted for publicatio

    Use of morphological, biochemical and molecular markers for early identification of an interspecific cucurbit hybrid (Cucurbita maxima x Cucurbita moschata)

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    El cultivar de zapallo Aconcagua INTA es un hibrido interespecífico (Cucurbita maxima x Cucurbita moschata) de amplia difusión en el país y que posee excelentes rindes, buen color y aptitud para el deshidratado. La producción de semilla implica el cruzamiento entre ambas especies parentales, previo asperjado con etephon del parental femenino, con el objetivo de ?castrar? los órganos masculinos florales y obtener flores predominantemente femeninas. Debido a que siempre hay un porcentaje de flores que escapan a la castración química, los lotes de semilla incluyen un porcentaje de semillas no hibridas, provenientes de la autofecundación del parental materno. Estos individuos poseen fenotipo diferente al del cultivar, por lo que debe cuantificarse su presencia en los lotes de semilla. Con ese fin, en este trabajo se analizaron comparativamente marcadores morfológicos (basado en caracteres de la hoja), bioquímicos (análisis proteico por UTLIEF) y moleculares (con el marcador microsatélite CMBR22) para la identificación temprana del hibrido Aconcagua INTA y sus parentales. Los tres métodos permitieron identificar inequívocamente al hibrido y sus parentales, presentando correspondencia absoluta (100%) entre ellos, en las plantas analizadas. Los marcadores proteicos y moleculares permitirán la identificación temprana de híbridos de zapallo cv. Aconcagua.Aconcagua INTA is an Argentine widespread cucurbit cultivar with high yield and suitability for the dehydration industry, developed from an interspecific cross (Cucurbita maxima x Cucurbita moschata). Its seed production involves the use of etephon in the maternal progenitor to castrate male flower organs, while the other line serves a pollen donor. Because this process is not totally effective, some hermaphrodite flowers remain in the maternal line, leading to self-pollination and –therefore- seeds of non-hybrid origin, which are phenotypically different from the hybrid. Thus, the percentage of non-hybrid seeds needs to be estimated and labelled in commercial seed lots of this cultivar. To this end, the present study analyzed, comparatively, morphological, biochemical and molecular markers that may be used for the early identification of this hybrid and its parental lines. Thus, a morphological marker based on leaf characteristics, protein profiles by UTLIEF, and the microsatellite molecular marker CMBR22, were evaluated in hybrid and parental plants. All three marker systems were able to accurately identify the hybrid and the parental lines, with results revealing 100% correspondence among the three types of markers. The protein and molecular markers developed herein represent a valuable tool for the early identification of hybrids in seed lots of cv. Aconcagua INTA.Fil: Tarnowski, C. G.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Valdez, Jorge Gustavo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Lorello, Inés María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Barboza Rojas, Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Cavagnaro, Pablo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Della Gaspera, Pedro Gustavo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentin

    Use of morphological, biochemical and molecular markers for early identification of an interspecific cucurbit hybrid (Cucurbita maxima x Cucurbita moschata)

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    El cultivar de zapallo Aconcagua INTA es un hibrido interespecífico (Cucurbita maxima x Cucurbita moschata) de amplia difusión en el país y que posee excelentes rindes, buen color y aptitud para el deshidratado. La producción de semilla implica el cruzamiento entre ambas especies parentales, previo asperjado con etephon del parental femenino, con el objetivo de ?castrar? los órganos masculinos florales y obtener flores predominantemente femeninas. Debido a que siempre hay un porcentaje de flores que escapan a la castración química, los lotes de semilla incluyen un porcentaje de semillas no hibridas, provenientes de la autofecundación del parental materno. Estos individuos poseen fenotipo diferente al del cultivar, por lo que debe cuantificarse su presencia en los lotes de semilla. Con ese fin, en este trabajo se analizaron comparativamente marcadores morfológicos (basado en caracteres de la hoja), bioquímicos (análisis proteico por UTLIEF) y moleculares (con el marcador microsatélite CMBR22) para la identificación temprana del hibrido Aconcagua INTA y sus parentales. Los tres métodos permitieron identificar inequívocamente al hibrido y sus parentales, presentando correspondencia absoluta (100%) entre ellos, en las plantas analizadas. Los marcadores proteicos y moleculares permitirán la identificación temprana de híbridos de zapallo cv. Aconcagua.Aconcagua INTA is an Argentine widespread cucurbit cultivar with high yield and suitability for the dehydration industry, developed from an interspecific cross (Cucurbita maxima x Cucurbita moschata). Its seed production involves the use of etephon in the maternal progenitor to castrate male flower organs, while the other line serves a pollen donor. Because this process is not totally effective, some hermaphrodite flowers remain in the maternal line, leading to self-pollination and –therefore- seeds of non-hybrid origin, which are phenotypically different from the hybrid. Thus, the percentage of non-hybrid seeds needs to be estimated and labelled in commercial seed lots of this cultivar. To this end, the present study analyzed, comparatively, morphological, biochemical and molecular markers that may be used for the early identification of this hybrid and its parental lines. Thus, a morphological marker based on leaf characteristics, protein profiles by UTLIEF, and the microsatellite molecular marker CMBR22, were evaluated in hybrid and parental plants. All three marker systems were able to accurately identify the hybrid and the parental lines, with results revealing 100% correspondence among the three types of markers. The protein and molecular markers developed herein represent a valuable tool for the early identification of hybrids in seed lots of cv. Aconcagua INTA.Fil: Tarnowski, C. G.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Valdez, Jorge Gustavo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Lorello, Inés María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Barboza Rojas, Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Cavagnaro, Pablo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Della Gaspera, Pedro Gustavo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentin

    Mineral maturity and crystallinity index are distinct characteristics of bone mineral

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    The purpose of this study was to test the hypothesis that mineral maturity and crystallinity index are two different characteristics of bone mineral. To this end, Fourier transform infrared microspectroscopy (FTIRM) was used. To test our hypothesis, synthetic apatites and human bone samples were used for the validation of the two parameters using FTIRM. Iliac crest samples from seven human controls and two with skeletal fluorosis were analyzed at the bone structural unit (BSU) level by FTIRM on sections 2–4 lm thick. Mineral maturity and crystallinity index were highly correlated in synthetic apatites but poorly correlated in normal human bone. In skeletal fluorosis, crystallinity index was increased and maturity decreased, supporting the fact of separate measurement of these two parameters. Moreover, results obtained in fluorosis suggested that mineral characteristics can be modified independently of bone remodeling. In conclusion, mineral maturity and crystallinity index are two different parameters measured separately by FTIRM and offering new perspectives to assess bone mineral traits in osteoporosis

    A Pilot Trial to Compare the Long-Term Efficacy of Pulmonary Vein Isolation with High-Power Short-Duration Radiofrequency Versus Laser Energy with Rapid Ablation Mode

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    Background: Pulmonary vein (PV) reconnection is the major cause of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). The probability of reconnection is higher if the primary lesion is not sufficiently effective, which can be unmasked with an adenosine provocation test (APT). High-power short-duration radiofrequency energy (HPSD) guided with ablation index (AI) and the third generation of the visually guided laser balloon (VGLB) are new methods for PVI. Methods: A total of 70 participants (35 in each group) who underwent a PVI with either AI-guided HPSD (50 W; AI 500 for the anterior and 400 for the posterior wall, respectively) or VGLB ablation were included in this observational pilot trial. Twenty minutes after each PVI, an APT was performed. The primary endpoint was the event-free survival from AF after three years. Results: A total of 137 (100%) PVs in the HPSD arm and 131 PVs (98.5%) in the VGLB arm were initially successfully isolated (p = 0.24). The overall procedure duration was similar in both arms (155 ± 39 in HPSD vs. 175 ± 58 min in VGLB, p = 0.191). Fluoroscopy time, left atrial dwelling time and duration from the first to the last ablation were longer in the VGLB arm (23 ± 8 vs. 12 ± 3 min, p < 0.001; 157 (111–185) vs. 134 (104–154) min, p = 0.049; 92(59–108) vs. 72 (43–85) min, p = 0.010). A total of 127 (93%) in the HPSD arm and 126 (95%) PVs in the VGLB arm remained isolated after APT (p = 0.34). The primary endpoint was met 1107 ± 68 days after ablation in 71% vs. 66% in the VGLB and HPSD arms, respectively (p = 0.65). Conclusions: HPSD and VGLB did not differ with respect to long-term outcome of PVI. A large, randomized study should be conducted to compare clinical outcomes with respect to these new ablation techniques

    A comparison of the physical and chemical differences between cancellous and cortical bovine bone mineral at two ages

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    To assess possible differences between the mineral phases of cortical and cancellous bone, the structure and composition of isolated bovine mineral crystals from young (1–3 months) and old (4–5 years) postnatal bovine animals were analyzed by a variety of complementary techniques: chemical analyses, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and 31P solid-state magic angle spinning nuclear magnetic resonance spectroscopy (NMR). This combination of methods represents the most complete physicochemical characterization of cancellous and cortical bone mineral completed thus far. Spectra obtained from XRD, FTIR, and 31P NMR all confirmed that the mineral was calcium phosphate in the form of carbonated apatite; however, a crystal maturation process was evident between the young and old and between cancellous and cortical mineral crystals. Two-way analyses of variance showed larger increases of crystal size and Ca/P ratio for the cortical vs. cancellous bone of 1–3 month than the 4–5 year animals. The Ca/(P + CO3) remained nearly constant within a given bone type and in both bone types at 4–5 years. The carbonate and phosphate FTIR band ratios revealed a decrease of labile ions with age and in cortical, relative to cancellous, bone. Overall, the same aging or maturation trends were observed for young vs. old and cancellous vs. cortical. Based on the larger proportion of newly formed bone in cancellous bone relative to cortical bone, the major differences between the cancellous and cortical mineral crystals must be ascribed to differences in average age of the crystals

    Mineral Composition is Altered by Osteoblast Expression of an Engineered Gs-Coupled Receptor

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    Activation of the Gs G protein–coupled receptor Rs1 in osteoblasts increases bone mineral density by 5- to 15-fold in mice and recapitulates histologic aspects of fibrous dysplasia of the bone. However, the effects of constitutive Gs signaling on bone tissue quality are not known. The goal of this study was to determine bone tissue quality in mice resulting from osteoblast-specific constitutive Gs activation, by the complementary techniques of FTIR spectroscopy and synchrotron radiation micro-computed tomography (SRμCT). Col1(2.3)-tTA/TetO-Rs1 double transgenic (DT) mice, which showed osteoblast-specific constitutive Gs signaling activity by the Rs1 receptor, were created. Femora and calvariae of DT and wild-type (WT) mice (6 and 15 weeks old) were analyzed by FTIR spectroscopy. WT and DT femora (3 and 9 weeks old) were imaged by SRμCT. Mineral-to-matrix ratio was 25% lower (P = 0.010), carbonate-to-phosphate ratio was 20% higher (P = 0.025), crystallinity was 4% lower (P = 0.004), and cross-link ratio was 11% lower (P = 0.025) in 6-week DT bone. Differences persisted in 15-week animals. Quantitative SRμCT analysis revealed substantial differences in mean values and heterogeneity of tissue mineral density (TMD). TMD values were 1,156 ± 100 and 711 ± 251 mg/cm3 (mean ± SD) in WT and DT femoral diaphyses, respectively, at 3 weeks. Similar differences were found in 9-week animals. These results demonstrate that continuous Gs activation in murine osteoblasts leads to deposition of immature bone tissue with reduced mineralization. Our findings suggest that bone tissue quality may be an important contributor to increased fracture risk in fibrous dysplasia patients
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