Round shadows in the thoracic roentgen picture, nicotine abuse

A 69 year old male patient was seen at our outpatient clinic because of a paravertebral mass in the routine x-ray-film of the chest. The patient was in good health, showed no loss of weight and complained only of slight cough probably due to his smoking habits. In view of these findings a benign lung tumor was suspected. However, the computed tomography of the chest revealed an aneurysm of the descending aorta which was successfully operated.     

Toughening of epoxy resin using synthesized polyurethane prepolymer based on hydroxyl-terminated polyesters

Epoxy resins are increasingly finding applications in the field of structural engineering. A wide variety of epoxy resins are available, and some of them are characterized by a relatively low toughness. One approach to improve epoxy resin toughness includes the addition of either a rigid phase or a rubbery phase. A more recent approach to toughen brittle polymers is through interpenetrating network (IPN) grafting. It has been found that the mechanical properties of polymer materials with an IPN structure are fairly superior to those of ordinary polymers. Therefore, the present work deals with epoxy resin toughening using a polyurethane (PU) prepolymer as modifier via IPN grafting. For this purpose, a PU prepolymer based on hydroxyl-terminated polyester has been synthesized and used as a modifier at different concentrations. First, the PU-based hydroxyl-terminated polyester has been characterized. Next, an IPN (Epoxy–PU) has been prepared and characterized using Fourier transform infrared (FTIR) spectroscopy, thin-layer chromatography (TLC), and scanning electron microscopy (SEM) prior to mechanical testing in terms of impact strength and toughness. In this study, a Desmophen 1200-based PU prepolymer was used as a modifier at different concentrations within the epoxy resin. The results also showed that, further to the IPN formation, the epoxy and the PU prepolymer reacted chemically (via grafting). Compared to virgin resin, the effect on the mechanical properties was minor. The impact strength varies from 3–9 J/m and K_c from 0.9–1.2 MPa m^1/2. Furthermore, the incorporation of a chain extender with the PU prepolymer as a modifier into the mixture caused a drastic improvement in toughness. The impact strength increases continuously and reaches a maximum value (seven-fold that of virgin resin) at a modifier critical concentration (40 phr). K_c reaches 2.5 MPa m^1/2 compared to 0.9 MPa m^1/2 of the virgin resin. Finally, the SEM analysis results suggested that internal cavitation of the modifier particles followed by localized plastics shear yielding is probably the prevailing toughening mechanism for the epoxy resin considered in the present study. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2603–2618, 1998     

Entropy generation due to natural convection from a horizontal isothermal cylinder in oil

Local entropy generation due to natural convection from a heated horizontal isothermal cylinder in oil was investigated numerically. The effect of viscous dissipation on entropy generation profiles was studied over a wide range of Rayleigh and Brinkman numbers. The results showed that viscous dissipation had minimal effect on entropy generation even when using a highly viscous oil.     

Cloud point extraction of 2,4−dichlorophenol from aqueous samples employing β−cyclodextrin

In this study, β?cyclodextrin (β?CD) was used to enhance the extraction of 2,4?dichlorophenol (2,4?DCP) from the aqueous sample in cloud point extraction (CPE) using spectrophotometric method. Several parameters have been investigated with and without the presence of β?CD modifier, such as pH, equilibration temperature, analyte concentration, and water content in the CPE and CPE?βCD systems, respectively. Equilibrium data are described by the Langmuir isotherm in both CPE systems with and without β?CD modifier. The thermodynamic parameters (positive values of ΔH° and ΔS°, negative values of ΔG°) indicate that the solubilization of 2,4?DCP in a polyethylene glycol silicone surfactant (DC193C) is endothermic, entropy gained, and spontaneous in both systems. In the CPE?βCD system, the results show that the β?CD modifier is capable of enhancing the extraction of 2,4?DCP pollutant from aqueous samples.     

Biological Screening of Newly Synthesized BIAN N-Heterocyclic Gold Carbene Complexes in Zebrafish Embryos

N-Heterocyclic carbene (NHC) metal complexes possess diverse biological activities but have yet to be extensively explored as potential chemotherapeutic agents. We have previously reported the synthesis of a new class of NHC metal complexes N-heterocyclic with acetate [IPr(BIAN)AuOAc] and chloride [IPr(BIAN)AuCl] ligands. In the experiments reported herein, the zebrafish embryos were exposed to serial dilutions of each of these complexes for 10–12 h. One hundred percent mortality was observed at concentrations ≥50 µM. At sub-lethal concentrations (10–30 µM), both compounds influenced zebrafish embryonic development. However, quite diverse categories of abnormalities were found in exposed embryos with each compound. Severe brain deformation and notochord degeneration were evident in the case of [IPr(BIAN)AuOAc]. The zebrafish embryos treated with [IPr(BIAN)AuCl] exhibited stunted growth and consequently had smaller body sizes. A depletion of 30%–40% glutathione was detected in the treated embryos, which could account for one of the possible mechanism of neurotoxicity. The fact that these compounds are capable of both affecting the growth and also compromising antioxidant systems by elevating intracellular ROS production implies that they could play an important role as a new breed of therapeutic molecules.     

Compostable composites of wheat stalk micro- and nanocrystalline cellulose and poly(butylene adipate-co-terephthalate): Surface properties and degradation behavior

An agricultural waste, the wheat stalk, was used for the extraction of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) via a series of thermochemical and mechanical treatments. The MCC and NCC were then compounded with the biodegradable polymer, poly(butylene adipate-co-terephthalate), PBAT, by melt mixing. The properties of the composites were evaluated by soil composting, contact angle and water absorption measurements, scanning electron microscopy (SEM) and gel permeation chromatography (GPC). The cellulosic filler was found, as per SEM results, to uniformly disperse in the polymer matrix forming a quite homogeneous composite which visibly degraded completely within a few months under soil composting and showed high water absorption, these properties being enhanced with the filler content. Compared to the neat PBAT, the composites showed enhanced surface hydrophilicity thereby increasing the ability of degradation. In spite of seemingly remarkable change in mechanical stability of the polymers under soil burial for several months, relatively low lowering of the molecular weight was observed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48149.