A case of severe corneal flattening after Descemet stripping endothelial keratoplasty.

PURPOSE: To report a case of extreme corneal flattening after initially uneventful Descemet stripping endothelial keratoplasty (DSEK). METHODS: A 76-year-old man underwent uneventful DSEK for pseudophakic bullous keratopathy (PBK) in his left eye. Postoperative evaluations were performed using anterior segment optical coherence tomography and biomicroscopy. RESULTS: The DSEK graft showed full adherence to the host stroma. Two weeks after surgery, the transplanted cornea developed pronounced flattening of the central corneal curvature accompanied by graft folds and remained unchanged until the most recent follow-up 20 weeks after surgery. CONCLUSIONS: Severe corneal flattening may be an undescribed complication occurring after uneventful DSEK, without any concomitant ocular pathology or detectable cause.

Probing photoelectrochemical processes in Au-CdS nanoparticle arrays by surface plasmon resonance: application for the detection of acetylcholine esterase inhibitors.

The photoelectrochemical charging of Au-nanoparticles (NP) in a Au-nanoparticle/CdS-nanoparticle array assembled on a Au-coated glass surface is followed by means of surface plasmon resonance (SPR) spectroscopy upon continuous irradiation of the sample. The charging of the Au-NPs results in the enhanced coupling between the localized surface plasmon of the Au-NP and the surface plasmon of the bulk surface, leading to a shift in the plasmon angle. The charging effect of the Au-NPs is supported by concomitant electrochemical experiments in the dark. Analysis of the results indicates that ca. 4.2 electrons are associated with each Au-nanoparticle under steady-state irradiation. The photoelectrochemical charging effect of the Au-NPs in the Au-CdS NP array is employed to develop a SPR sensor for acetylcholine esterase inhibitors.

Au nanoparticle-enhanced surface plasmon resonance sensing of biocatalytic transformations.

N-(3-Aminopropyl)-N'-methyl-4,4'-bipyridinium is coupled to tiopronin-capped Au nanoparticles (diameter ca. 2 nm) to yield methyl(aminopropyl)viologen-functionalized Au nanoparticles (MPAV(2+)-Au nanoparticles). In situ electrochemical surface plasmon resonance (SPR) measurements are used to follow the electrochemical deposition of the bipyridinium radical cation modified Au nanoparticles on an Au-coated glass surface and the reoxidation and dissolution of the bipyridinium radical cation film. The MPAV(2+)-functionalized Au nanoparticles are also employed for the amplified SPR detection of NAD(+) and NADH cofactors. By SPR monitoring the partial biocatalyzed dissolution of the bipyridinium radical cation film in the presence of diaphorase (DP) NAD(+) is detected in the concentration range of 1x10(-4) M to 2x10(-3) M. Similarly, the diaphorase-mediated formation of the bipyridinium radical cation film on the Au-coated glass surface by the reduction of the MPAV(2+)-functionalized Au nanoparticles by NADH is used for the amplified SPR detection of NADH in the concentration range of 1x10(-4) M to 1x10(-3) M.

Analysis of NAD(P)+/NAD(P)H cofactors by imprinted polymer membranes associated with ion-sensitive field-effect transistor devices and Au-quartz crystals.

Specific recognition sites for the NAD(P)+ and NAD(P)H cofactors are imprinted in a cross-linked acrylamide-acrylamidophenylboronic acid copolymer membrane. The imprinted membranes, associated with pH-sensitive field-effect transistors (ISFETs) or Au-quartz piezoelectric crystals, enable the potentiometric or microgravimetric analysis of the oxidized NAD(P)+ cofactors and the reduced NAD(P)H cofactors, respectively. The NAD+- and NADP+-imprinted membranes associated with the ISFET allow the analysis of NAD+ and NADP+ with sensitivities that correspond to 15.0 and 18.0 mVdecade(-1) and detection limits of 4 x 10(-7) and 2 x 10(-7) M, respectively. The NADH- and NADPH-imprinted membranes associated with the ISFET device enable the analysis of NADH and NADPH with sensitivities that correspond to 24.2 and 21.8 mV x decade(-1) and lower detection limits that are 1 x 10(-7) and 2 x 10(-7) M, respectively. The ISFET devices functionalized with the NADH and NADPH membranes are employed in the analysis of the biocatalyzed oxidation of lactic acid and ethanol in the presence of lactate dehydrogenase and alcohol dehydrogenase, respectively.

Selective sensing of triazine herbicides in imprinted membranes using ion-sensitive field-effect transistors and microgravimetric quartz crystal microbalance measurements.

A series of triazine herbicides consisting of the chlorotriazine atranex (atrazine), (1), prozinex, (2), tyllanex, (3), simanex, (4) and the methylthiolated triazines ametrex, (5), prometrex, (6) and terbutex, (7), were imprinted in an acrylamide-methacrylate copolymer. The polymer was deposited on the gate surface of ion-sensitive field-effect transistors (ISFETs) and piezoelectric Au-quartz crystals. Selective sensing of the imprinted substrates was accomplished by the imprinted polymer membrane associated with the ISFETs and Au-quartz crystals. Binding of the substrates onto the imprinted polymer associated with the gate of the ISFET alters the electrical charge and potential of the gate interface, thus allowing the potentiometric transduction of the binding events. The association of the substrates with the imprinted membrane linked to the Au-quartz crystal results in the membrane swelling, thus enabling the microgravimetric quartz crystal microbalance assay of the substrate binding events. The specificity of the imprinted recognition sites is attributed to complementary H-bond and electrostatic interactions between the substrates and the acrylamide-methacrylic acid copolymer.