1,724 research outputs found
Graft Suturing for Lenticule Dislocation after Descemet Stripping Automated Endothelial Keratoplasty
Purpose: To report the mid-term outcomes of graft suturing in a patient with lenticule dislocation after Descemet stripping automated endothelial keratoplasty (DSAEK).
Case Report: A 78-year old woman was found to have graft dislocation involving the nasal half of the cornea after uneventful DSAEK. Graft repositioning, refilling the anterior chamber with air, and placement of four full-thickness 10/0 nylon sutures over the detached area were performed two weeks after the initial surgery. The sutures were removed 6 weeks later. Serial specular microscopy and anterior segment optical coherence tomography were performed. At 18 months, there was good lenticule apposition and a clear graft.
Conclusion: Anchoring sutures seem to be effective for management of graft detachment following DSAEK
Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors
The transition magnetic moment of a sterile-to-active neutrino conversion
gives rise to not only radiative decay of a sterile neutrino, but also its
non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass
as dark matter candidates, their decay signals are actively searched for in
cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic
ionization, which can be detected by direct dark matter experiments. It is
found that this inelastic scattering process for a nonrelativistic sterile
neutrino has a pronounced enhancement in the differential cross section at
energy transfer about half of its mass, manifesting experimentally as peaks in
the measurable energy spectra. The enhancement effects gradually smear out as
the sterile neutrino becomes relativistic. Using data taken with germanium
detectors that have fine energy resolution in keV and sub-keV regimes,
constraints on sterile neutrino mass and its transition magnetic moment are
derived and compared with those from astrophysical observations
Some pattern recognitions for a recommendation framework for higher education studentsâ generic competence development using machine learning
The project presented in this paper aims to formulate a recommendation framework that consolidates the higher education studentsâ particulars such as their academic background, current study and student activity records, their attended higher education institutionâs expectations of graduate attributes and self-assessment of their own generic competencies. The gap between the higher education studentsâ generic competence development and their current statuses such as their academic performance and their student activity involvement was incorporated into the framework to come up with a recommendation for the student activities that lead to their generic competence development. For the formulation of the recommendation framework, the data mining tool Orange with some programming in Python and machine learning models was applied on 14,556 studentsâ activity and academic records in the case higher education institution to find out three major types of patterns between the studentsâ participation of the student activities and (1) their academic performance change, (2) their programmes of studies, and (3) their English results in the public examination. These findings are also discussed in this paperPeer Reviewe
Electrostatic Contribution of Surface Charge Residues to the Stability of a Thermophilic Protein: Benchmarking Experimental and Predicted pKa Values
Optimization of the surface charges is a promising strategy for increasing thermostability of proteins. Electrostatic contribution of ionizable groups to the protein stability can be estimated from the differences between the pKa values in the folded and unfolded states of a protein. Using this pKa-shift approach, we experimentally measured the electrostatic contribution of all aspartate and glutamate residues to the stability of a thermophilic ribosomal protein L30e from Thermococcus celer. The pKa values in the unfolded state were found to be similar to model compound pKas. The pKa values in both the folded and unfolded states obtained at 298 and 333 K were similar, suggesting that electrostatic contribution of ionizable groups to the protein stability were insensitive to temperature changes. The experimental pKa values for the L30e protein in the folded state were used as a benchmark to test the robustness of pKa prediction by various computational methods such as H++, MCCE, MEAD, pKD, PropKa, and UHBD. Although the predicted pKa values were affected by crystal contacts that may alter the side-chain conformation of surface charged residues, most computational methods performed well, with correlation coefficients between experimental and calculated pKa values ranging from 0.49 to 0.91 (p<0.01). The changes in protein stability derived from the experimental pKa-shift approach correlate well (râ=â0.81) with those obtained from stability measurements of charge-to-alanine substituted variants of the L30e protein. Our results demonstrate that the knowledge of the pKa values in the folded state provides sufficient rationale for the redesign of protein surface charges leading to improved protein stability
Chemoenzymatic elaboration of monosaccharides using engineered cytochrome P450_(BM3) demethylases
Polysaccharides comprise an extremely important class of biopolymers
that play critical roles in a wide range of biological processes,
but the synthesis of these compounds is challenging because of
their complex structures. We have developed a chemoenzymatic
method for regioselective deprotection of monosaccharide substrates
using engineered Bacillus megaterium cytochrome P450
(P450_(BM3)) demethylases that provides a highly efficient means
to access valuable intermediates, which can be converted to a
wide range of substituted monosaccharides and polysaccharides.
Demethylases displaying high levels of regioselectivity toward a
number of protected monosaccharides were identified using a
combination of protein and substrate engineering, suggesting that
this approach ultimately could be used in the synthesis of a wide
range of substituted mono- and polysaccharides for studies in
chemistry, biology, and medicine
Identification of Human Sperm Antigens to Antisperm Antibodies *
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98396/1/j.1600-0897.1983.tb00243.x.pd
Saccharide Display on Microtiter Plates
AbstractNew insight into the importance of carbohydrates in biological systems underscores the need for rapid synthetic and screening procedures for them. Development of an organic synthesis-compatible linker that would attach saccharides to microtiter plates was therefore undertaken to facilitate research in glycobiology. Galactosyllipids containing small, hydrophobic groups at the anomeric position were screened for noncovalent binding to microtiter plates. When the lipid component was a saturated hydrocarbon between 13 and 15 carbons in length, the monosaccharide showed complete retention after aqueous washing and could be utilized in biological assays. This alkyl chain was also successfully employed with more complex oligosaccharides in biological assays. In light of these findings, this method of attachment of oligosaccharides to microtiter plates should be highly efficacious to high-throughput synthesis and analyses of carbohydrates in biological assays
Constraints on millicharged particles with low threshold germanium detectors at Kuo-Sheng Reactor Neutrino Laboratory
Relativistic millicharged particles () have been proposed in various
extensions to the Standard Model of particle physics. We consider the scenarios
where they are produced at nuclear reactor core and via interactions of
cosmic-rays with the earth's atmosphere. Millicharged particles could also be
candidates for dark matter, and become relativistic through acceleration by
supernova explosion shock waves. The atomic ionization cross section of
with matter are derived with the equivalent photon approximation.
Smoking-gun signatures with significant enhancement in the differential cross
section are identified. New limits on the mass and charge of are
derived, using data taken with a point-contact germanium detector with 500g
mass functioning at an energy threshold of 300~eV at the Kuo-Sheng Reactor
Neutrino Laboratory.Comment: 8 pages, 7 figure
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