Search

Zeba A Syed,1 Gustavo Rosa Gameiro,1 Marco Ruggeri,1 Amr Elsawy,1,2 Ibrahim Sayed-Ahmed,1 Vatookarn Roongpoovapatr,1 Mohamed Abdel-Mottaleb,2 Mohamed Abou Shousha11Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; 2Department of Electrical and Computer Engineering, University of Miami College of Engineering, Coral Gables, FL, USAObjective: We present a novel method for screening eye bank donor corneas using high definition optical coherence tomography (HD-OCT). This technology allows for the quantification of endothelial/Descemet membrane (En/DM) complex thickness ex vivo.Design: Prospective interventional study.Participants: Fifty-two corneal grafts from 27 donors were included in this study. Twenty additional control eyes and 11 eyes with Fuchs’ endothelial corneal dystrophy were also evaluated for comparison.Methods: A custom built, high speed HD-OCT device (Envisu R2210, Bioptigen, Buffalo Grove, IL, USA) was used to obtain images, and custom-made graph-based segmentation software was used to automatically deconstruct corneal images into micro-layers. HD-OCT imaging was used to scan through the sealed sterile case of donor corneas stored in McCarey-Kaufman medium to image their En/DM complex through the center of the cornea.Results: This technology allowed for quantification of En/DM complex thickness in all donor corneas through the sealed sterile container used to transport graft tissue. Mean En/DM complex thickness of donor corneas was 17±4 μm. The difference between donor cornea En/DM thickness and that of control subjects (16±2 μm) was not statistically significant (p=0.3), suggesting that the transport container and media do not affect measurements. There was a significant difference between En/DM thickness of Fuchs’ endothelial corneal dystrophy eyes (25±5 μm) and both donor corneas (p

Ultraviolet (UV) radiation is harmful to the skin. Therefore, it capitalized on the properties of thiophene and pyridine derivatives to prepare new textile‐protective agents with improved UV protection factor (UPF) factor. This embodies the preparation and characterization of "2‐((3‐cyano‐4‐(4‐methoxyphenyl)‐6‐(thiophene‐2‐yl)pyridine‐2‐yl)oxy)acetohydrazide" (HZ) in complex with Ni(II), Cu(II), Zn(II), or Cd(II), using proton nuclear magnetic resonance (1H NMR), carbon‐13 nuclear magnetic resonance (13C NMR), X‐ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal analysis techniques. Characterization of cotton fabric‐based cellulose (CELL) in complex with the synthesized agents using FTIR spectroscopy, X‐ray spectroscopy, and scanning electron microscopy–energy dispersive X‐ray analysis (SEM–EDX) revealed deposition of the hydrazide and its metal complexes on the cellulosic fiber. Interestingly, cellulose complexation with Cu(II) was observed to have the highest value of the UPF. Computation of the reactivity indices using density functional theory (DFT) supports this finding, where the electrophilicity parameter of the modified fabric was found to correlate with the UPF wherein Cu(II) shows the highest value. The synthesized complexes could, therefore, provide lead structures for developing new UV‐protective agents with enhanced coating characteristics. [ABSTRACT FROM AUTHOR]

Dye lasers are commonly used in optical investigation because their solutions in organic solvents deliver tunable, coherent emissions. They exhibit intense fluorescence owing to some specific spectroscopic characteristics. One drawback of the laser dyes is that it shows excessive triplet-state losses (TSLs.) The lack of theoretical predictions of fluorescence rates, intersystem crossing (ISC), and phosphorescence in laser dyes prompted us to report on the predicted rates of radiative and nonradiative transitions of some laser dyes. Structural engineering by some substituents influencing the simulated rates of coumarin laser dye derivatives for an efficient operation was investigated. The NH2 functional group renders the coumarin 120 more fluorescents with reduced TLS than the other investigated materials. Tailoring new efficient laser dyes can be achieved guided by the calculated rates of emission and nonradiative processes. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation (PCD) of ethanol in an inert atmosphere on catalysis was explored in a lab-scale experiment. A morphologically tuned nanostructured controlled ZnO and ZnO/TiO2 nanocomposites were synthesized using a simple hydrothermal process under the control of several functionally capping agents marking a milestone in photocatalysis. It is possible that this could be modified to produce photobiogas out of organic dye pollution. The photocatalysts were characterized by the use of X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer, Emmett, and Teller (BET) surface area analyzer, Scanning electron microscope (SEM-EDX), and UV–Vis absorption spectroscopy. The photocatalytic activity of the ZnO and ZnO–TiO2 composite nanostructures was evaluated for the photodegradation of the Tartrazine (Tr) dye aqueous solution. Where the composite matrix exhibits higher photocatalytic activity than pure ZnO nanomaterials as a result of the synergistic interaction between ZnO and TiO2 particles. This is mainly due to its higher surface area than pure ZnO. Moreover, the photocatalytic activity of the tuned nanostructured materials is found to be enhanced by the effect of the capping agent and controlling the morphology. This increase is accompanied by a significant shift in surface shape and band gap energy. According to the findings, the designed morphologies of pure ZnO photocatalyst impacted the formation of photobiogas from the photocatalytic decomposition of ethanol as a model of organic pollutants in wastewater. However, when using composite ZnO/TiO2 photocatalysts, the rate of CH4 formation is significantly lower than when using ZnO photocatalysts alone. This may be attributed to the synergetic effect between ZnO and TiO2 particles which leads to a remarkable reduction in the newly formed band gap energy. This may result in a fast rate of recombination between the photogenerated charge carriers (e− and h+). [ABSTRACT FROM AUTHOR]

With the continual progress in developing the forward osmosis (FO) membrane, in both industry and academia, it is prospected to remain the best alternative technique for the production of freshwater. The current paper focuses on the preparation and characterization of FO membranes and ZnO nanoparticles (ZnO NPs) that can be used for membrane modification to enhance its performance. FO membranes are fabricated in our labs from the cellulose acetate (CA) polymer by phase inversion methods. These membranes are easy to prepare, stable against bacterial attack, chemical, and mechanical changes, as well as showing excellent performance and superior economics. The optimum conditions for preparing forward osmosis cellulose acetate (FO-CA) membranes are; 7 wt.% CA, 92.75 wt.% acetone, and 0.25 wt.% ZnO NPs per unit percentage of CA in aqueous solution. A new approach for the modification of CA membranes using the synthesized ZnO NPs was shown to enhance the performance of membranes for forward osmosis water desalination process. We study the effect of polymer concentration, membrane thickness, and membrane modification by ZnO NPs on membrane performance. The fabricated membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance–Fourier transform infrared spectroscopy, and the mechanical properties were studied in order to expose the best membrane for water desalination and also the synthesized ZnO NPs were characterized by XRD and SEM. The performance of the CA/ZnO NPs membranes were examined using parameters, such as contact angle, surface area and pore size, water flux (Jw), and salt rejection (R%). Compared with the pure CA membrane, the CA membrane modified with ZnO NPs was more hydrophilic, with an improved water contact angle (~47.6 ± 2°) over the pure CA membrane (~63.85 ± 2°) and it showed improving in water flux (26.57 L h−1 m−2) over the pure CA membrane (19.42 L h−1 m−2), also it showed salt rejection 99.5% of Na+, 100% of Cl–, and 99.6% of Mg2+. The water flux increased in the case of CA membrane modified with ZnO NPs is due to increasing in surface area and total pore volume than the pure CA membrane by 23% and 20%, respectively. This demonstrates that the CA membrane modified with ZnO NPs can significantly improve the membrane performances and was suitable to enhance the selectivity, and water flux of the membranes for water desalination. [ABSTRACT FROM AUTHOR]

This study focuses on the surface modification of polyamide (PA) thin-film composite reverse osmosis (RO) membranes using irradiated chitosan/titanium dioxide (CS/TiO2) via Co60 gamma ray. This modification was achieved through coating of a thin layer of gamma preirradiated chitosan onto the surface of commercial PA thin film composite membrane. The chitosan concentrations ranged from 0.2 to 0.6 wt% with different contents of TiO2 nanoparticles irradiated at different doses. The surface morphology, surface hydrophilicity and membrane chemical composition before and after the modification were analyzed by scanning electron microscope (SEM), contact angle measurements and FT-IR spectroscopy. FT-IR spectroscopy of the synthesized membranes proved the incorporation of both CS and TiO2 nanoparticles on the polyamide active layer. The performance of both neat and modified membranes for water desalination was evaluated. The results showed an improvement in the permeate flux of the membranes by increasing TiO2 concentration up to 0.125 wt%, and then decreased at higher concentration of TiO2. Moreover, the salt rejection (%) increased at lower concentrations of TiO2 and then decreased with increasing the TiO2 content. Contact angle measurements revealed that the surface hydrophilicity of the membranes, improved by increasing TiO2 concentration in chitosan solution. [ABSTRACT FROM AUTHOR]

Trazodone was labeled with 99mTc by indirect method. More than 97% radiochemical yield was reached under the following optimized conditions: 100 µg of Trazodone, pH 7, 10 mg of glucoheptonate, 35 µg of stannous chloride, 185 MBq of 99mTc eluate, 20 min, room temperature. The in vitro stability and also the retention of the complex in the brain tissue allow the use of this complex as a potential brain imaging agent. [ABSTRACT FROM AUTHOR]