Removal of boron compounds in pressure-driven desalination of the Black Sea water

The article has investigated the process of removing boron from the water of the Black Sea during its pressure-driven desalination using an OPMN-P nanofiltration membrane (ZAO NTTs Vladipor) and an ESPA-1 reverse-osmosis membrane (Hydronautics). It has been shown that the boron removal degree in a two-stage treatment (nanofiltration and reverse osmosis) is much lower than in a single-stage one (reverse osmosis). For the first time it was shown that there is a substantial impact of salts of calcium and magnesium on the boron retention coefficient with reverse-osmosis membranes. We have studied the conditioning process in terms of the content of boron (using an Amberlite IRA-743 boron-containing sorbent and the method of reverse osmosis in the alkaline medium) permeate obtained in the two-stage desalination of the Black Sea water.     

Analysis and Optimization of a Synthetic Milkweed Floral Attractant for Mosquitoes

A pentane extract of flowers of common milkweed, Asclepias syriaca (Asclepiadaceae), elicited significant orientation from both male and female Culex pipiens in a dual-port flight olfactometer. Analysis of the extract by gas chromatography-mass spectrometry revealed six major constituents in order of relative abundance: benzaldehyde, (E)-β-ocimene, phenylacetaldehyde, benzyl alcohol, nonanal, and (E)-2-nonenal. Although not all were collected from the headspace profile of live flowers, a synthetic blend of these six compounds, when presented to mosquitoes in the same levels and proportions that occur in the extract, elicited a response comparable to the extract. Subtractive behavioral bioassays demonstrated that a three-component blend consisting of benzaldehyde, phenylacetaldehyde, and (E)-2-nonenal was as attractive as the full blend. These findings suggest the potential use of synthetic floral-odor blends for monitoring or control of both male and female disease-vectoring mosquitoes.     

Biodegradable microfabricated plug-filters for glaucoma drainage devices

We report on the development of a batch fabricated biodegradable truncated-cone-shaped plug filter to overcome the postoperative hypotony in nonvalved glaucoma drainage devices. Plug filters are composed of biodegradable polymers that disappear once wound healing and bleb formation has progressed past the stage where hypotony from overfiltration may cause complications in the human eye. The biodegradable nature of device eliminates the risks associated with permanent valves that may become blocked or influence the aqueous fluid flow rate in the long term. The plug-filter geometry simplifies its integration with commercial shunts. Aqueous humor outflow regulation is achieved by controlling the diameter of a laser-drilled through-hole. The batch compatible fabrication involves a modified SU-8 molding to achieve truncated-cone-shaped pillars, polydimethylsiloxane micromolding, and hot embossing of biodegradable polymers. The developed plug filter is 500?μm long with base and apex plane diameters of 500 and 300?μm, respectively, and incorporates a laser-drilled through-hole with 44-μm effective diameter in the center.     

New Flower-Shaped Lead(II) Coordination Polymer at the Nano Scale: Synthesis, Structural Characterization and DFT Calculations of [Pb(o-phen)(N3)2] n Containing the Pb-(μ1,1-N3)(μ1,3-N3) Motif

A new nano-flower lead(II) azido coordination polymer from the ligand, orthophenanthroline (o-phen), [Pb(o-phen)(μ_1,1-N₃)(μ_1,3-N₃)] _n (1), was synthesized by a sonochemical method. Compound 1 was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), elemental analyses and IR spectroscopy. Single crystalline material was obtained using a heat gradient applied to a solution of the reagents. The structure of 1 is a coordination polymer of lead(II) containing the Pb-(μ_1,1-N₃)(μ_1,3-N₃) motif, formed of one-dimensional chains. The structure of the 1 was optimized by density functional theory. Structural parameters and IR spectra for 1 are consistent with the crystal structure. Pure phase PbO nanoparticles were obtained by thermolysis of 1 with oleic acid as a surfactant at 180 and 200 °C an air. PbO nanoparticles were characterized by XRD and SEM.     

Effect of Fiber Acid Treatment on the Dynamic Mechanical Properties of Unsaturated Polyester/Carbon Fiber Unidirectional Composites

In this study, the surface modification of carbon fiber by sulfuric acid is investigated. Atomic Force Microscopy was employed to capture the corresponding changes in the surface roughness of the carbon fiber. Moreover, using treated and untreated fibers, unsaturated polyester unidirectional composite rods were prepared and their flexural properties were determined by three-point bending and dynamic mechanical thermal analysis.

The results indicated that the carbon fiber surface roughness increases in all samples. It is also found that treating the fiber decreases the magnitude of loss modulus. Besides, the flexural strength of composites made of the treated carbon fiber significantly increased.     

Virulence Factors of Enteric Pathogenic Escherichia coli: A Review

Escherichia coli are remarkably versatile microorganisms and important members of the normal intestinal microbiota of humans and animals. This harmless commensal organism can acquire a mixture of comprehensive mobile genetic elements that contain genes encoding virulence factors, becoming an emerging human pathogen capable of causing a broad spectrum of intestinal and extraintestinal diseases. Nine definite enteric E. coli pathotypes have been well characterized, causing diseases ranging from various gastrointestinal disorders to urinary tract infections. These pathotypes employ many virulence factors and effectors subverting the functions of host cells to mediate their virulence and pathogenesis. This review summarizes new developments in our understanding of diverse virulence factors associated with encoding genes used by different pathotypes of enteric pathogenic E. coli to cause intestinal and extraintestinal diseases in humans.     

Study of Emulsions of Solutions of Film-Forming Polymers in Methylene Chloride Related to the Problem of Microencapsulation of Proteins

The properties of oil-in-water, water-in-oil, and double emulsions of solutions of cellulose triacetate (CTA) and polycarbonate (PC) in methylene chloride containing aqueous solutions of a model protein, albumin, are investigated. Such emulsions are intended for production of microcapsules. The effect of the nature and concentration of the film-forming polymer on the particle size and polydispersity of the emulsions is established. The correlation of the viscosity, interfacial surface tension, and dispersity of oil-in-water emulsions of solutions of CTA and PC in methylene chloride is determined. It is shown that the dispersity of the emulsions increases with a decrease in the ratio of the viscosity of the disperse phase to the viscosity of the dispersion medium and the decrease in the interfacial surface tension.     

Rheological properties and crystallization behavior of modified polylactic acid using lauroyl peroxide and glycidyl methacrylate

The molecular structure of polylactic acid (PLA) was modified by lauroyl peroxide (LP) as an alkyl free radical and glycidyl methacrylate (GMA) as a reactive co-monomer. We investigated the effect of different preparation methods, that is, the melt and solution, on the structure and physical and mechanical properties of glycidyl methacrylate grafted polylactic acid (PLA-g-GMA). The Fourier transformed infrared spectroscopy (FTIR) was implemented to characterize the final products in order to confirm that GMA was successfully grafted onto PLA. The gel permeation chromatography showed that the molecular weight and polydispersity of the modified PLA were increased by grafting. However, by varying other parameters such as the reaction time and the LP and GMA concentrations, we observed that the resulting products from the melt method are richer in the rheological properties compared with those properties from the solution method. This is due to the different molecular weights resulted from the either preparation methods. From the DSC characteristics of PLA-g-GMA samples, the crystallization degree of the samples prepared from the melt method is greater than that of the solution method. Meanwhile, the cold crystallization for the PLA-g-GMA samples derived from the solution method occurs at higher temperatures compared with the cold crystallization of the samples resulted from the melt method.     

Shape memory thin films of polyurethane: Synthesis,characterization, and recovery behavior

Polyurethane thin films with inherent two phase segregated characters are exceptional candidates for the development of shape memory materials. However, controlling the phase behavior of such complex structures for decoding their recovery behavior still experiences its early stage of development. In this work, polyurethane thin films were synthesized based on two polyols, ester-based polyols (ESP), and ether-based polyols (ETP) together with diphenyl diisocyanate (MDI). The effects of ingredient ratio of PETP (ether-based prepolymer)/PESP (ester-based prepolymer) on the chemical structure and final properties of polyurethanes were studied by the Fourier-transformed infrared spectroscopy (FTIR), the differential scanning calorimetry (DSC), the scanning electron microscopy (SEM), the dynamic mechanical thermal analysis (DMTA), a tensiometer, and the atomic force microscopy (AFM). The shape memory behaviors were explored by the thermomechanical cycles applied by a DMTA device in the controlled force mode. The PU films showed various properties compared with the bulk PU since they formed spherulitic textures with different structures. All the PU films except PU-0 showed high shape recovery ca. 90% in the first cycle with a large glassy storage modulus in the range of 2,800–4,040MPa, and a recovery ratio enhanced by increasing the number of cycle to a maximum of 95%.