Near‐Infrared Intraoperative Chemiluminescence Imaging

Intraoperative imaging technologies recently entered the operating room, and their implementation is revolutionizing how physicians plan, monitor, and perform surgical interventions. In this work, we present a novel surgical imaging reporter system: intraoperative chemiluminescence imaging (ICI). To this end, we have leveraged the ability of a chemiluminescent metal complex to generate near‐infrared light upon exposure to an aqueous solution of Ce⁴⁺ in the presence of reducing tissue or blood components. An optical camera spatially resolves the resulting photon flux. We describe the construction and application of a prototype imaging setup, which achieves a detection limit as low as 6.9 pmol cm^?2 of the transition‐metal‐based ICI agent. As a proof of concept, we use ICI for the in vivo detection of our transition metal tracer following both systemic and subdermal injections. The very high signal‐to‐noise ratios make ICI an interesting candidate for the development of new intraoperative imaging technologies.     

Platinum on nitrogen doped graphene and tungsten carbide supports for ammonia electro-oxidation reaction

Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells, hydrogen production and understanding nitrogen cycle. Platinum has been established as the best electrocatalyst for ammonia oxidation in aqueous alkaline media. In this study, Pt/nitrogen-doped graphene (NDG) and Pt/tungsten monocarbide (WC)/NDG are synthesized by a wet chemistry method and their ammonia oxidation activities are compared to commercial Pt/C. Pt/NDG exhibits a specific activity of 0.472 mA∙cm^–2, which is 44% higher than commercial Pt/C, thus establishing NDG as a more effective support than carbon black. Moreover, it is demonstrated that WC as a support also impacts the activity with further 30% increase in comparison to NDG. Surface modification with Ir resulted in the best electrocatalytic activity with Pt-Ir/WC/NDG having almost thrice the current density of commercial Pt/C. This work adds insights regarding the role of NDG and WC as efficient supports along with significant impact of Ir surface modification.     

Analytical models for the series resistance of selective emitters in silicon solar cells including the effect of busbars

A theoretical analysis of the power loss and series resistance of the front side emitter in silicon solar cells is presented. Existing 1D models (infinitely long finger) and 2D models (including the effect of busbars) of emitter series resistance contribution are extended to the case of selective emitters. The general case of different current densities for both emitters in the selective emitter scheme is considered in these extensions. The resulting models depend on the individual sheet resistances and current densities in both emitters and the device's overall grid geometry. The models are corroborated by finite element simulation of the potential in the emitter. An excellent agreement is found between the analytical models, and the simulations for a wide range of sheet resistances typically encountered in silicon solar cells. Grid simulations using the 2D model are applied to solar cells with selective emitters, where the width of the low‐resistive emitter was varied. The simulations demonstrate that the 2D model can explain the absolute change in fill factor observed in these cells. Copyright © 2013 John Wiley & Sons, Ltd.     

A monolithically integrated high‐efficiency Cu(In,Ga)Se2 mini‐module structured solely by laser

Monolithically integrated Cu(In,Ga)Se₂ mini‐modules were fabricated in order to reduce the width of patterning related dead area. The Cu(In,Ga)Se₂ layers were prepared on soda‐lime glasses using the multistage process at low substrate temperature below 500 °C. A picosecond laser with a wavelength of 532 nm was used for all of the structuring processes (P1, P2, and P3) for the monolithic integration. A “lift‐off” type structuring was applied for P1 and P3, and an “ablation” type was for P2. The laser structuring was optimized to be minimizing the dead area width, and the width of about 70 µm was successfully achieved. A mini‐module, in which the optimized structuring processes were applied for the integration, demonstrated a certified efficiency of 16.6%. Copyright © 2015 John Wiley & Sons, Ltd.     

Design and realization of transparent solar modules based on luminescent solar concentrators integrating nanostructured photonic crystals

Herein, we present a prototype of a photovoltaic module that combines a luminescent solar concentrator integrating one‐dimensional photonic crystals and in‐plane CuInGaSe₂ (CIGS) solar cells. Highly uniform and wide‐area nanostructured multilayers with photonic crystal properties were deposited by a cost‐efficient and scalable liquid processing amenable to large‐scale fabrication. Their role is to both maximize light absorption in the targeted spectral range, determined by the fluorophore employed, and minimize losses caused by emission at angles within the escape cone of the planar concentrator. From a structural perspective, the porous nature of the layers facilitates the integration with the thermoplastic polymers typically used to encapsulate and seal these modules. Judicious design of the module geometry, as well as of the optical properties of the dielectric mirrors employed, allows optimizing light guiding and hence photovoltaic performance while preserving a great deal of transparency. Optimized in‐plane designs like the one herein proposed are of relevance for building integrated photovoltaics, as ease of fabrication, long‐term stability and improved performance are simultaneously achieved. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

The influence of impregnation condition on reinforced ethylene–vinyl–acetate elastomer composite

Experiments were conducted to investigate the effect of impregnation conditions on glass fiber-reinforced ethylene–vinyl–acetate elastomer. Both the matrix elastomer resin and reinforcing glass fiber were premixed and compression-molded using a specially constructed mold. The mold prevents the flowing out of the matrix resin during fabrication. The impregnation time was varied between 5 and 25 min. The level of impregnation was measured through the optical micrographs of the cross section, estimation of void contents using the ignition method, and transverse bending strength. The morphology of the fractured surface was studied using scanning electron microscopy (SEM). The results showed that the longer the impregnation time, the lower the void contents. Both the bending modulus and strength increased with increasing impregnation time. The SEM micrograph shows little adhesion between the matrix and the reinforcing glass fiber. © 1996 John Wiley & Sons, Inc.     

Production and purification of a fused recombinant protein gp-36 (HIV-2) from Escherichia coli

A fragment of the gp-36 gene of the Human Immunodeficiency Virus type 2 (HIV-2) was fused to a stabilizer sequence, which encodes for the first N-terminal 58 amino acids of the human interleukin-2. The fused protein was expressed under the control of the tryptophan promoter in Escherichia coli, and expressed as 20% of the total cellular protein. Transmission electron microscopy indicated that the fusion protein formed cytoplasmic insoluble inclusion bodies. Inclusion bodies were semipurified by a wash pellet cell procedure, rendering a material with a purity higher than 70% by SDS–polyacrylamide gel electrophoresis. After solubilization with urea, this preparation was further purified by gel-filtration chromatography up to 95% purity.     

Anionic synthesis of aromatic carboxyl functionalized polymers. Chain-end functionalization of poly(styryl)lithium with 4,5-dihydro-4,4-dimethyl-2-[4-(1-phenylethenyl)phenyl] oxazole

The novel syntheses of 4-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)benzophenone, 1-[4-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)phenyl]-1-phenylethanol and 4,5-dihydro-4,4-dimethyl-2-[4-(1-phenylethenyl)phenyl]oxazole ( 1 ) are described. ω-Oxazolyl polystyrene ( 2 ) was synthesized in quantitative yields by the reaction of poly(styryl)lithium with stoichiometric amounts of 4,5-dihydro-4,4-dimethyl-2-[4-(1-phenylethenyl)phenyl]oxazole ( 1 ) in toluene/tetrahydrofuran (4 : 1 v/v) at −78°C. Deblocking of the oxazoline protecting group by acid hydrolysis followed by saponification quantitatively provides the corresponding aromatic carboxyl chain-end functionalized polystyrene ( 3 ). The functionalization agent and functionalized polymers were characterized by HPLC, thin layer chromatography, size exclusion chromatography, vapor phase osmometry, spectroscopy (¹H NMR, ¹³C NMR and FTIR), potentiometry and elemental analysis.     

Assessing support alternatives for longwall gateroads subject to changing stress

Longwall gateroad entries are subject to changing horizontal and vertical stress induced by redistribution of loads around the extracted panel. The stress changes can result in significant deformation of the entries that may include roof sag, rib dilation, and floor heave. Mine operators install different types of supports to control the ground response and maintain safe access and ventilation of the longwall face. This paper describes recent research aimed at quantifying the effect of longwall-induced stress changes on ground stability and using the information to assess support alternatives. The research included monitoring of ground and support interaction at several operating longwall mines in the U.S., analysis and calibration of numerical models that adequately represent the bedded rock mass, and observation of the support systems and their response to changes in stress. The models were then used to investigate the impact of geology and stress conditions on ground deformation and support response for various depths of cover and geologic scenarios. The research results were summarized in two regression equations that can be used to estimate the likely roof deformation and height of roof yield due to longwall-induced stress changes. This information is then used to assess the ability of support systems to maintain the stability of the roof. The application of the method is demonstrated with a retrospective analysis of the support performance at an operating longwall mine that experienced a headgate roof fall. The method is shown to produce realistic estimates of gateroad entry stability and support performance, allowing alternative support systems to be assessed during the design and planning stage of longwall operations.