9,604 research outputs found
Optical studies of transparent ferroelectric strontium-barium niobate/silica nanocomposite
Author name used in this publication: C. L. MakAuthor name used in this publication: K. H. Wong2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Retarding Progression of Myopia with Seasonal Modification of Topical Atropine
Purpose: To investigate whether seasonal modification in the concentration of atropine drops is effective in retarding the progression of myopia.
Methods: Two hundred and forty eyes of 120 healthy preschool- and school-age children in Chiayi region, Taiwan were recruited. The treatment group consisted of 126 eyes of 63 children who received atropine eye drops daily for one year and the control group included 114 eyes of 57 children who received nothing. The concentration of atropine eye drops was modified by seasonal variation as follows: 0.1% for summer, 0.25% for spring and fall, and 0.5% for winter. Refractive error, visual acuity, intraocular pressure (IOP), and axial length were evaluated before and after intervention.
Results: Mean age was 9.1±2.8 years in the atropine group versus 9.3±2.8 years in controls (P=0.88). Mean spherical equivalent, refractive error and astigmatism were -1.90±1.66 diopters (D) and -0.50±0.59 D in the atropine group; corresponding values in the control group were -2.09±1.67 D (P=0.97) and -0.55±0.60 D (P=0.85), respectively. After one year, mean progression of myopia was 0.28±0.75 D in the atropine group vs 1.23±0.44 D in controls (P<0.001). Myopic progression was significantly correlated with an increase in axial length in both atropine (r=0.297, P=0.001) and control (r=0.348, P<0.001) groups. No correlation was observed between myopic progression and IOP in either study group.
Conclusion: Modifying the concentration of atropine drops based on seasonal variation, seems to be effective and tolerable for retarding myopic progression in preschool- to school-age children
High tunability in compositionally graded epitaxial barium strontium titanate thin films by pulsed-laser deposition
2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Photoluminescence of transparent strontium–barium–niobate-doped silica nanocomposites
Author name used in this publication: C. L. MakAuthor name used in this publication: K. H. Wong2001-2002 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Prevention of hepatocellular carcinoma in chronic viral hepatitis B and C infection
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide, with the majority of cases associated with persistent infection from hepatitis B virus (HBV) or hepatitis C virus (HCV). Natural history studies have identified risk factors associated with HCC development among chronic HBV and HCV infection. High-risk infected individuals can now be identified by the usage of risk predictive scores. Vaccination plays a central role in the prevention of HBV-related HCC. Treatment of chronic HBV infection, especially by nucleoside analogue therapy, could also reduce the risk of HBV-related HCC. Concerning HCV infection, besides the advocation of universal precautions to reduce the rate of infection, pegylated interferon and ribavirin could also reduce the risk of HCV-related HCC among those achieving a sustained virologic response. Recently there has been mounting evidence on the role of chemopreventive agents in reducing HBV- and HCV-related HCC. The continued advances in the understanding of the molecular pathogenesis of HCC would hold promise in preventing this highly lethal cancer.published_or_final_versio
Temperature-insensitive interferometer using a highly birefringent photonic crystal fiber loop mirror
Author name used in this publication: M. S. Demokan2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
On the Performance Prediction of BLAS-based Tensor Contractions
Tensor operations are surging as the computational building blocks for a
variety of scientific simulations and the development of high-performance
kernels for such operations is known to be a challenging task. While for
operations on one- and two-dimensional tensors there exist standardized
interfaces and highly-optimized libraries (BLAS), for higher dimensional
tensors neither standards nor highly-tuned implementations exist yet. In this
paper, we consider contractions between two tensors of arbitrary dimensionality
and take on the challenge of generating high-performance implementations by
resorting to sequences of BLAS kernels. The approach consists in breaking the
contraction down into operations that only involve matrices or vectors. Since
in general there are many alternative ways of decomposing a contraction, we are
able to methodically derive a large family of algorithms. The main contribution
of this paper is a systematic methodology to accurately identify the fastest
algorithms in the bunch, without executing them. The goal is instead
accomplished with the help of a set of cache-aware micro-benchmarks for the
underlying BLAS kernels. The predictions we construct from such benchmarks
allow us to reliably single out the best-performing algorithms in a tiny
fraction of the time taken by the direct execution of the algorithms.Comment: Submitted to PMBS1
Flip Distance Between Triangulations of a Simple Polygon is NP-Complete
Let T be a triangulation of a simple polygon. A flip in T is the operation of
removing one diagonal of T and adding a different one such that the resulting
graph is again a triangulation. The flip distance between two triangulations is
the smallest number of flips required to transform one triangulation into the
other. For the special case of convex polygons, the problem of determining the
shortest flip distance between two triangulations is equivalent to determining
the rotation distance between two binary trees, a central problem which is
still open after over 25 years of intensive study. We show that computing the
flip distance between two triangulations of a simple polygon is NP-complete.
This complements a recent result that shows APX-hardness of determining the
flip distance between two triangulations of a planar point set.Comment: Accepted versio
Effect of a nonlinear photonic crystal fiber on the noise characterization of a distributed Raman amplifier
Author name used in this publication: M. S. Demokan2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Magnetoelectric photocurrent generated by direct interband transitions in InGaAs/InAlAs two-dimensional electron gas
We report the observation of magnetoelectric photocurrent generated via direct interband transitions in an InGaAs/InAlAs two-dimensional electron gas by a linearly polarized incident light. The electric current is proportional to the in-plane magnetic field, which unbalances the velocities of the photoexcited carriers with opposite spins and consequently generates the electric current from a hidden spin photocurrent. The spin photocurrent can be evaluated from the measured electric current, and the conversion coefficient of spin photocurrent to electric current is self-consistently estimated to be 10-3-10 -2 per Tesla. The observed light-polarization dependence of the electric current is well explained by a theoretical model which reveals the wave vector angle dependence of the photoexcited carrier density. © 2010 The American Physical Society.published_or_final_versio
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