985 research outputs found

    Use of a T-flex toric intraocular lens to correct clinically significant astigmatism

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    AbstractPurposeTo investigate the stability and effectiveness of T-flex toric intraocular lenses (IOLs) for the correction of regular corneal astigmatism during cataract surgery.MethodsFrom October 2009 to January 2014 we enrolled patients receiving phacoemulsification and T-flex toric IOL implantation in the capsular bag at the Far Eastern Memorial Hospital. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal astigmatism, refractive astigmatism, and the degree to which the IOL axis deviated from the demanded axis were recorded both before the operation and 6 months postoperatively.ResultsWe enrolled 24 eyes of 24 consecutive patients in this study. The mean spherical power of the implanted toric IOLs was 17.13 ± 4.21 D (range 6.0–24.0 D) and the mean cylindrical power of the IOLs was 3.0 ± 0.86 D (range 2.0–5.0 D). At the 6-month follow up examination, the refractive astigmatism had improved from 3.21 ± 1.50 D to 0.77 ± 0.47 D (p < 0.001) and the spherical equivalence had improved from 4.47 ± 5.43 D to 0.63 ± 0.49 D (p = 0.007). The CDVA improved from 0.81 ± 0.45 logMAR to 0.09 ± 0.11 logMAR (p < 0.001). The mean improvement from the preoperative CDVA to the postoperative UDVA was 5.3 lines on the Snellen chart. Ninety-two percent of our patients achieved a postoperative UDVA ≥20/40 and 67% achieved a postoperative UDVA ≥20/25.ConclusionThe T-flex toric IOL can effectively reduce visually significant corneal astigmatism and improve uncorrected distance visual acuity during cataract surgery

    Experimental and numerical investigation of an air-to-water heat pipe-based heat exchanger

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    An experimental and analytical investigation was conducted on an air-to-water heat exchanger equipped with six wickless heat pipes (thermosyphons) charged with water as the working fluid. The flow pattern consisted of a double pass on the evaporator and condenser sections. The six thermosyphons were all made from carbon steel, measured 2m in length and were installed in a staggered arrangement. The objectives of the reported experimental investigation were to analyse the effect of multiple air passes at different air inlet temperatures (100 to 250°C) and air mass flow rates (0.05 to 0.14kg/s) on the thermal performance of the heat exchanger unit including the heat pipes. The results were compared with a CFD model that assumed the heat pipes were solid rods with a constant conductivity. The conductivity of the pipes was extracted from modifications of correlations available in the literature based around the theory of Thermal Resistance. The results proved to be very accurate within 10% of the experimental values

    Pauli blocking and final-state interaction in electron-nucleus quasielastic scattering

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    The nucleon final-state interaction in inclusive electron-nucleus quasielastic scattering is studied. Based on the unitarity equation satisfied by the scattering-wave operators, a doorway model is developed to take into account the final-state interaction including the Pauli blocking of nucleon knockout. The model uses only experimental form factors as the input and can be readily applied to light- and medium-mass nuclei. Pauli blocking effects in these latter nuclei are illustrated with the case of the Coulomb interaction. Significant effects are noted for beam energies below ~ 350 MeV and for low momentum transfers.Comment: 16 pages, 6 figure

    Approach to the semiconductor cavity QED in high-Q regimes with q-deformed boson

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    The high density Frenkel exciton which interacts with a single mode microcavity field is dealed with in the framework of the q-deformed boson. It is shown that the q-defomation of bosonic commutation relations is satisfied naturally by the exciton operators when the low density limit is deviated. An analytical expression of the physical spectrum for the exciton is given by using of the dressed states of the cavity field and the exciton. We also give the numerical study and compare the theoretical results with the experimental resultsComment: 6 pages, 2 figure

    q-exponential, Weibull, and q-Weibull distributions: an empirical analysis

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    In a comparative study, the q-exponential and Weibull distributions are employed to investigate frequency distributions of basketball baskets, cyclone victims, brand-name drugs by retail sales, and highway length. In order to analyze the intermediate cases, a distribution, the q-Weibull one, which interpolates the q-exponential and Weibull ones, is introduced. It is verified that the basketball baskets distribution is well described by a q-exponential, whereas the cyclone victims and brand-name drugs by retail sales ones are better adjusted by a Weibull distribution. On the other hand, for highway length the q-exponential and Weibull distributions do not give satisfactory adjustment, being necessary to employ the q-Weibull distribution. Furthermore, the introduction of this interpolating distribution gives an illumination from the point of view of the stretched exponential against inverse power law (q-exponential with q > 1) controversy.Comment: 6 pages, Latex. To appear in Physica

    Contributions of dry and wet depositions of polychlorinated dibenzo-p-dioxins and dibenzofurans to a contaminated site resulting from a penetachlorophenol manufacturing process

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    The soils at a factory for manufacturing pentachlorophenol were heavily contaminated by polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In order to verify the contributions of dry and wet deposition of PCDD/Fs from the ambient air, the concentration of PCDD/Fs in ambient air and soil were measured, the partition of particle- and gas-phases of atmospheric PCDD/Fs was calculated, and the annual fluxes of total dry and wet PCDD/F depositions were modeled. Average atmospheric PCDD/F concentration was 1.24 ng Nm (-aEuro parts per thousand 3) (or 0.0397 ng I-TEQ Nm (-aEuro parts per thousand 3)). Moreover, over 92.8% of total PCDD/Fs were in the particle phase, and the dominant species were high chlorinated congeners. The total PCDD/F fluxes of dry and wet deposition were 119.5 ng m (-aEuro parts per thousand 2) year (-aEuro parts per thousand 1) (1.34 ng I-TEQ m (-aEuro parts per thousand 2) year (-aEuro parts per thousand 1)) and 82.0 ng m (-aEuro parts per thousand 2) year (-aEuro parts per thousand 1) (1.07 ng I-TEQ m (-aEuro parts per thousand 2) year (-aEuro parts per thousand 1)), respectively. By scenario simulation, the total fluxes of dry and wet PCDD/F depositions were 87.1 and 68.6 ng I-TEQ, respectively. However, the estimated PCDD/F contents in the contaminated soil were 839.9 mu g I-TEQ. Hence, the contributions of total depositions of atmospheric PCDD/F were only 0.02%. The results indicated that the major sources of PCDD/F for the contaminated soil could be attributed to the pentachlorophenol manufacturing process

    On derivation of Euler-Lagrange Equations for incompressible energy-minimizers

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    We prove that any distribution qq satisfying the equation q=÷f\nabla q=\div{\bf f} for some tensor f=(fji),fjihr(U){\bf f}=(f^i_j), f^i_j\in h^r(U) (1r<1\leq r<\infty) -the {\it local Hardy space}, qq is in hrh^r, and is locally represented by the sum of singular integrals of fjif^i_j with Calder\'on-Zygmund kernel. As a consequence, we prove the existence and the local representation of the hydrostatic pressure pp (modulo constant) associated with incompressible elastic energy-minimizing deformation u{\bf u} satisfying u2,cofu2h1|\nabla {\bf u}|^2, |{\rm cof}\nabla{\bf u}|^2\in h^1. We also derive the system of Euler-Lagrange equations for incompressible local minimizers u{\bf u} that are in the space Kloc1,3K^{1,3}_{\rm loc}; partially resolving a long standing problem. For H\"older continuous pressure pp, we obtain partial regularity of area-preserving minimizers.Comment: 23 page

    Adiponectin Prevents Diabetic Premature Senescence of Endothelial Progenitor Cells and Promotes Endothelial Repair by Suppressing the p38 MAP Kinase/p16INK4A Signaling Pathway

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    OBJECTIVE - A reduced number of circulating endothelial progenitor cells (EPCs) are casually associated with the cardiovascular complication of diabetes. Adiponectin exerts multiple protective effects against cardiovascular disease, independent of its insulin-sensitizing activity. The objective of this study was to investigate whether adiponectin plays a role in modulating the bioavailability of circulating EPCs and endothelial repair. RESEARCH DESIGN AND METHODS - Adiponectin knockout mice were crossed with db+/- mice to produce db/db diabetic mice without adiponectin. Circulating number of EPCs were analyzed by flow cytometry. Reendothelialization was evaluated by staining with Evans blue after wire-induced carotid injury. RESULTS - In adiponectin knockout mice, the number of circulating EPCs decreased in an age-dependent manner compared with the wild-type controls, and this difference was reversed by the chronic infusion of recombinant adiponectin. In db/db diabetic mice, the lack of adiponectin aggravated the hyperglycemia-induced decrease in circulating EPCs and also diminished the stimulatory effects of the PPARγ agonist rosiglitazone on EPC production and reendothelialization. In EPCs isolated from both human peripheral blood and mouse bone marrow, treatment with adiponectin prevented high glucose-induced premature senescence. At the molecular level, adiponectin decreased high glucose-induced accumulation of intracellular reactive oxygen species and consequently suppressed activation of p38 MAP kinase (MAPK) and expression of the senescence marker p16INK4A. CONCLUSIONS - Adiponectin prevents EPC senescence by inhibiting the ROS/p38 MAPK/p16 INK4A signaling cascade. The protective effects of adiponectin against diabetes vascular complications are attributed in part to its ability to counteract hyperglycemia-mediated decrease in the number of circulating EPCs. © 2010 by the American Diabetes Association.published_or_final_versio
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