Mitomycin-C in congenital glaucoma

BACKGROUND AND OBJECTIVE: To evaluate the adjunctive use of mitomycin-C (MMC) during trabeculotomy and trabeculectomy for eyes with high-risk congenital glaucoma. PATIENTS AND METHODS: A prospective, randomized, double-blind study was performed to compare the effect of a single, 4-minute intraoperative exposure to 0.2 mg/ml (group 1) or 0.4 mg/ml (group 2) of MMC on trabeculotomy with trabeculectomy in 16 high-risk cases (30 eyes) of congenital glaucoma. RESULTS: The preoperative and final postoperative intraocular pressures (IOPs) of the two groups did not differ significantly. At the final follow-up, IOP control (< 21 mm Hg) without medications was achieved in 60% of the eyes in group 1 and in 86.67% of the eyes in group 2 (P = 21). With medication, IOP control was achieved in 86.7% of the eyes of each group. In both groups, the rate of surgical failure was 13.3%. Avascular, thin, sharply demarcated blebs were noted in 33.3% of the eyes from group 1 and in 66.67% of those from group 2 (P = .14). Intraoperative and postoperative hyphema and postoperative hypotony were the complications encountered in both groups, whereas serous choroidal detachment and wound leakage were seen only in group 2. CONCLUSIONS: Intraoperative MMC applied at a concentration of 0.2 mg/ml controlled postoperative IOP as effectively as a 0.4-mg/ml concentration in high-risk cases of congenital glaucoma, but with a lower incidence of complications and thin-walled blebs.     

Effect of Hydrophobicity and Temperature on the Interactions in the Mixed Micelles of Triblock Polymers [(EO76PO29EO76) and (EO19PO69EO19)] with Monomeric and Gemini Surfactants

The interactions in the mixed micelles of two triblock polymers, F68 (EO₇₆PO₂₉EO₇₆) and P123 (EO₁₉PO₆₉EO₁₉), with a series of monomeric (dodecyltrimethyl ammonium bromide, tetradecyltrimethyl ammonium bromide and cetyltrimethyl ammonium bromide) and gemini {dimethylene bis(alkyldimethyl ammonium bromide), m-2-m, where m = 10, 12 and 14} cationic surfactants were studied by surface tension and viscosity measurements in aqueous solutions at different temperatures. The mixed micellar and interfacial properties of the binary mixtures were analyzed using Clint, Rubingh, Rosen and Maeda approaches. Both F68 and P123 show weak interactions with the studied cationic surfactants at 298.15 K which become favorable (synergistic) at higher temperatures. Further, the synergistic interactions are more in mixtures of P123 than F68 at higher temperatures. A comparison of the effects of number of EO and PO blocks in triblock polymers on various physicochemical parameters of the mixed micelles has also been made. The unfavorable enthalpy changes are compensated by favorable entropy changes as a result of the hydrophobic effect. The relative viscosity (η _r) studies show that the size of the micelles formed by pure P123 is smaller than those of F68. The values of η _r for the mixed micelles of F68 show significant variation with chain length of gemini surfactants whereas no such effect is seen in mixtures with P123.     

Role of PbSe Structural Stabilization in Photovoltaic Cells

Semiconductor nanocrystals are promising materials for printed optoelectronic devices, but their high surface areas are susceptible to forming defects that hinder charge carrier transport. Furthermore, correlation of chalcogenide nanocrystal (NC) material properties with solar cell operation is not straightforward due to the disorder often induced into NC films during processing. Here, an improvement in long‐range ordering of PbSe NCs symmetry that results from halide surface passivation is described, and the effects on chemical, optical, and photovoltaic device properties are investigated. Notably, this passivation method leads to a nanometer‐scale rearrangement of PbSe NCs during ligand exchange, improving the long‐range ordering of nanocrystal symmetry entirely with inorganic surface chemistry. Solar cells constructed with a variety of architectures show varying improvement and suggest that triplet formation and ionization, rather than carrier transport, is the limiting factor in singlet fission solar cells. Compared to existing protocols, our synthesis leads to PbSe nanocrystals with surface‐bound chloride ions, reduced sub‐bandgap absorption and robust materials and devices that retain performance characteristics many hours longer than their unpassivated counterparts.     

A novel photogalvanic cell using anthraquinone-2-sulfonate

A photoelectrochemical cell based on the photochemistry of anthraquinone-2-sulfonate (D) has been set up. In the presence of formate at pH 11.0, D on illumination produces D^? or D^2?. In the absence of oxygen, at the platinum electrode the anodic reaction is D^? → D + e, or D^2? → D + 2e, and at the dark electrode the cathodic reaction is O₂ + 2H₂O + 4e → 4OH^?. The open circuit potential of the cell is 500 mV. The short circuit current is 180 μA. The cell has been recycled at least eight times. The efficiency increases with platinized platinum electrode in the dark chamber. The steady current under illumination is 65 μA with the same open circuit voltage of 500 mV. The short circuit current is 250 μA. With a CdS electrode in the illuminated chamber the efficiency is even better. The open circuit voltage is 560 mV. After charging by illumination for 8 h a steady current of 120 μA can be drawn from the cell, with illumination off, for 40 h. The short circuit current is 450 μA. The maximum power output is 4.2 × 10^?6W The cell can be recycled at least four times without any loss in efficiency. Grey deposition on the CdS electrode possibly indicates electrode decomposition.     

Atmospheric microplasma jet: spectroscopic database development and analytical results

This paper presents a developed dielectric-barrier-discharge-based "sniffer" that offers unique characteristics not available from other techniques. It is a portable, highly specific, and sensitive detector that operates at atmospheric pressure. It provides both molecular and elemental information on organic and inorganic gases and particulate aerosols. Measurements were made to electrically characterize the plasma and calculate the energy coupled into the plasma. We created a signature database for diverse chemicals based on the atomic and diatomic emission spectrum that serves to classify the compound and ideally recognize it by composition with the optical emission intensity corresponding to concentration. For some operational regimes and species, emission from OH (A(2)Σ(+)-X(2)Π), CH (A(2)Δ-X(2)Π), and often C(2) (d(3)Π(g)-a(3)Π(u); Swan band system) diatomic radicals is produced. Limits of detection extend to parts per billion (ppb) levels for some species such as decane, 2-decanol, and nitrobenzene. Results are presented for differentiation of classes of organic compounds such as alkanes, aromatics, oxygenates, chlorinated, and nitrogen-containing organic compounds.     

Mechanical Properties of Conjugated Polymers and Polymer‐Fullerene Composites as a Function of Molecular Structure

Despite the importance of mechanical compliance in most applications of semiconducting polymers, the effects of structural parameters of these materials on their mechanical properties are typically not emphasized. This paper examines the effect of length of the pendant group on the tensile modulus and brittleness for a series of regioregular poly(3‐alkylthiophenes) (P3ATs) and their blends with a soluble fullerene derivative, PCBM. The tensile modulus decreases with increasing length of the alkyl side‐chain, from 1.87 GPa for butyl side chains to 0.16 GPa for dodecyl chains. The moduli of P3AT:PCBM blends films are greater than those of the pure polymers by factors of 2–4. A theoretical model produces a trend in the effect of alkyl side chain on tensile modulus that follows closely to the experimental measurements. Tensile modulus correlates with brittleness, as the strain at which cracks appear is 6% for P3BT and >60% for P3OT. Adhesion of the P3AT film to a polydimethylsiloxane (PDMS) substrate is believed to play a role in an apparent increase in brittleness from P3OT to P3DDT. The additive 1,8‐Diiodooctane (DIO) reduces the modulus of P3HT:PCBM blend by a factor of 3. These results could enable mechanically robust, flexible, and stretchable electronics.