Improved corneal clarity following lamellar keratectomy for corneal lipidosis in a canine with ocular manifestations of hypothyroidism.

OBJECTIVE: To report the corneal clarity outcome following lamellar keratectomy of arcus lipoides corneae secondary to canine hypothyroidism and report a unique retinal manifestation of systemic disease. ANIMAL STUDIED: Four-year-old spayed female Sheepdog-Poodle canine. PROCEDURE: Lamellar keratectomy OD. RESULTS: Bilateral severe arcus lipoides corneae was noted in the initial presentation. Bilateral, symmetric, and multifocal bullous retinal detachments were observed at subsequent visits. Biochemical testing revealed hyperlipidemia presumed to be associated with primary acquired thyroiditis. Corneal clarity and visual behaviors were significantly improved following unilateral lamellar keratectomy with no evidence of recurrence within the year following surgery. Bilateral retinal detachments and hyperlipidemia resolved months after initiation of thyroxine supplementation. Corneal lipidosis in the untreated eye remained static. CONCLUSIONS: Lamellar keratectomy is a viable surgical option for the treatment of arcus lipoides corneae. Hypothyroidism should be considered a differential diagnosis for spontaneous, bilateral, multifocal, and serous retinal detachments.

Feline post-sterilization hyphema.

OBJECTIVE: To determine incidence and risk factors of post-sterilization hyphema in shelter cats. ANIMALS STUDIED: Retrospective medical record review of 1204 cats and prospective screening of 195 cats. PROCEDURES: The study consisted of three parts: (a) Survey responses were collected from 20 veterinarians, who perform high-quality high-volume spay-neuter (HQHVSN) in both shelter and public clinic settings; (b) medical records of 1204 cats were analyzed retrospectively over a 14-month time period; and (c) ophthalmic examinations, including tonometry, were performed prospectively on 195 cats before and after sterilization surgery over 8 weeks. RESULTS: Nine of 20 surveyed veterinarians reported having witnessed hyphema in cats following sterilization surgery. Retrospective review of 1204 medical record and prospective screening of 195 cats showed that three juvenile (<1 year of age) male cats (<2 kg) developed hyphema within 1 hour following surgery (0.2% incidence). In all three affected cats, anesthesia was induced with tiletamine/zolazepam (3 of 523 cats induced with this drug combination; 0.6% incidence), and hyphema resolved within 20 hours. Mean intraocular pressures as measured by Icare® TonoVet were (mean ± standard deviation) 11.5 ± 3.8 mm Hg and 21.7 ± 4.6 mm Hg for juvenile (<1 year of age) and adult (>1 year of age) cats, respectively. CONCLUSIONS: Survey responses and three observed cases confirm the existence of feline post-sterilization hyphema with an estimated incidence of 0.2%. The underlying mechanism for this occurrence remains unknown.

Evaluation of leak pressure and closure time for double-layer esophagotomy closure with an interrupted or a continuous suture pattern.

OBJECTIVE To compare the leak pressure and amount of time required to perform closure for 2 double-layer esophagotomy closure techniques. SAMPLE 28 intrathoracic esophageal segments harvested from 38 porcine cadavers. PROCEDURES Longitudinal 3-cm esophagotomy incisions made in porcine cadaveric esophagi were closed with 2 double-layer closure techniques. Fifteen incisions were closed with a simple interrupted pattern, and 13 incisions were closed with a simple continuous pattern. Leak pressure, bursting wall tension, and closure time were compared between suture patterns by use of a t test or Mann-Whitney rank sum test. RESULTS Median leak pressures differed significantly between segments closed with the simple interrupted pattern (16.0 mm Hg; range, 5.4 to 54.9 mm Hg) and the simple continuous pattern (38.7 mm Hg; range, 11.3 to 81.9 mm Hg). Median bursting wall tension differed significantly between the simple interrupted pattern (0.63 × 105 dynes/cm; range, 0.16 × 105 dynes/cm to 2.89 × 105 dynes/cm) and the simple continuous pattern (1.79 × 105 dynes/cm; range, 0.44 × 105 dynes/cm to 4.70 × 105 dynes/cm). Mean ± SD closure time differed significantly between the simple interrupted pattern (19.2 ± 2.0 minutes) and the simple continuous pattern (14.7 ± 1.5 minutes). CONCLUSIONS AND CLINICAL RELEVANCE In the study reported here, double-layer simple continuous closure resulted in a higher median postoperative leak pressure and higher median postoperative bursting wall tension and could be performed more rapidly than the double-layer simple interrupted closure on these porcine cadaveric specimens.

Germanium terminated (1 0 0) diamond.

An ordered germanium terminated (1 0 0) diamond surface has been formed and characterised using a combination of low energy electron diffraction and synchrotron-based core level photoemission spectroscopy. A number of preparation methods are explored, in each case inducing a two domain [Formula: see text] surface reconstruction. The surface becomes saturated with bonded germanium such that each [Formula: see text] unit cell hosts 1.26 Ge atoms on average, and possesses a negative electron affinity of -0.71 eV.

A graphene field-effect transistor as a molecule-specific probe of DNA nucleobases.

Fast and reliable DNA sequencing is a long-standing target in biomedical research. Recent advances in graphene-based electrical sensors have demonstrated their unprecedented sensitivity to adsorbed molecules, which holds great promise for label-free DNA sequencing technology. To date, the proposed sequencing approaches rely on the ability of graphene electric devices to probe molecular-specific interactions with a graphene surface. Here we experimentally demonstrate the use of graphene field-effect transistors (GFETs) as probes of the presence of a layer of individual DNA nucleobases adsorbed on the graphene surface. We show that GFETs are able to measure distinct coverage-dependent conductance signatures upon adsorption of the four different DNA nucleobases; a result that can be attributed to the formation of an interface dipole field. Comparison between experimental GFET results and synchrotron-based material analysis allowed prediction of the ultimate device sensitivity, and assessment of the feasibility of single nucleobase sensing with graphene.

Graphene field effect transistor as a probe of electronic structure and charge transfer at organic molecule-graphene interfaces.

The electronic structure of physisorbed molecules containing aromatic nitrogen heterocycles (triazine and melamine) on graphene is studied using a combination of electronic transport, X-ray photoemission spectroscopy and density functional theory calculations. The interfacial electronic structure and charge transfer of weakly coupled molecules on graphene is found to be governed by work function differences, molecular dipole moments and polarization effects. We demonstrate that molecular depolarization plays a significant role in these charge transfer mechanisms even at submonolayer coverage, particularly for molecules which possess strong dipoles. Electronic transport measurements show a reduction of graphene conductivity and charge carrier mobility upon the adsorption of the physisorbed molecules. This effect is attributed to the formation of additional electron scattering sites in graphene by the molecules and local molecular electric fields. Our results show that adsorbed molecules containing polar functional groups on graphene exhibit different coverage behaviour to nonpolar molecules. These effects open up a range of new opportunities for recognition of different molecules on graphene-based sensor devices.

Air-stable electron depletion of Bi(2)Se(3) using molybdenum trioxide into the topological regime.

We perform high-resolution photoelectron spectroscopy on in situ cleaved topological insulator Bi2Se3 single crystals and in situ transport measurements on Bi2Se3 films grown by molecular beam epitaxy. We demonstrate efficient electron depletion of Bi2Se3 via vacuum deposition of molecular MoO3, lowering the surface Fermi energy to within ∼100 meV of the Dirac point, well into the topological regime. A 100 nm MoO3 film provides an air-stable doping and passivation layer.