Cyclophosphamide removal from water by nanofiltration and reverse osmosis membrane

The rejection of cyclophosphamide (CP) by nanofiltration (NF) and reverse osmosis (RO) membranes from ultrapure (Milli-Q) water and membrane bioreactor (MBR) effluent was investigated. Lyophilization-extraction and detection methods were first developed for CP analysis in different water matrices. Experimental results showed that the RO membrane provided excellent rejection (>90%) under all operating conditions. Conversely, efficiency of CP rejection by NF membrane was poor: in the range of 20-40% from Milli-Q water and around 60% from MBR effluent. Trans-membrane pressure, initial CP concentration and ionic strength of the feed solution had almost no effect on CP retention by NF. On the other hand, the water matrix proved to have a great influence: CP rejection rate by NF was clearly enhanced when MBR effluent was used as the background solution. Membrane fouling and interactions between the CP and water matrix appeared to contribute to the higher rejection of CP.     

Emergence of genomic self-similarity in location independent representations

A key property for predicting the effectiveness of stochastic search techniques, including evolutionary algorithms, is the existence of a positive correlation between the form and the quality of candidate solutions. In this paper we show that when the ordering of genomic symbols in a genetic algorithm is completely independent of the fitness function and therefore free to evolve along with the candidate solutions it encodes, the resulting genomes self-organize into self-similar structures that favor this key stochastic search property.     

High Aspect Ratio Sub‐Micrometer Channels Using Wet Etching: Application to the Dynamics of Red Blood Cell Transiting through Biomimetic Splenic Slits

Nanoparticles delivering drugs, disseminating cancer cells, and red blood cells (RBCs) during splenic filtration must deform and pass through the sub‐micrometer and high aspect ratio interstices between the endothelial cells lining blood vessels. The dynamics of passage of particles/cells through these slit‐like interstices remain poorly understood because the in vitro reproduction of slits with physiological dimensions in devices compatible with optical microscopy observations requires expensive technologies. Here, novel microfluidic PDMS devices containing high aspect ratio slits with sub‐micrometer width are molded on silicon masters using a simple, inexpensive, and highly flexible method combining standard UV lithography and anisotropic wet etching. These devices enabled revealing novel modes of deformations of healthy and diseased RBCs squeezing through splenic‐like slits (0.6–2 × 5–10 × 1.6–11 µm³) under physiological interstitial pressures. At the slit exit, the cytoskeleton of spherocytic RBCs seemed to be detached from the lipid membrane whereas RBCs from healthy donors and patients with sickle cell disease exhibited peculiar tips at their front. These tips disappeared much slower in patients' cells, allowing estimating a threefold increase in RBC cytoplasmic viscosity in sickle cell disease. Measurements of time and rate of RBC sequestration in the slits allowed quantifying the massive trapping of spherocytic RBCs.     

Silk Hydrogel Microfibers for Biomimetic Fibrous Material Design

Fiber units are conserved design motifs that bestow intrinsic stiffness to biological tissues. Collagen fibrils are the fundamental unit of fibrous tissues with controlled assembly and multiscale structure‐function properties. Characteristic non‐linear tissue response is afforded through energy dissipation at the stiff‐soft interfaces of fibril collagen and extrafibrillar matrix components. The goal of this research is to develop a 3D silk hydrogel microfiber platform with bioinspired toughening mechanisms. Batch fabrication and post‐processing renders fibers that can be handled and with tunable features, as well as loading of components to improve material responses. Matrix loading of a glycoprotein, bovine serum albumin (BSA), adds a primary defense mechanism to material failure in the form of sacrificial bonds. This enables nano‐ to micro‐scale rearrangement with strain and improved fiber toughness compared to silk‐only fibers. Further biomimicry is added via matrix loading of a biosilica precursor peptide, R5, enabling biomineralization in the form of silicification. Inorganic mineral deposition of Silk‐BSA‐R5 hydrogel microfibers provides a fibrous scaffold for applications that require fibril‐mineral interfaces for load transduction. This microfiber platform introduces a methodology for meticulous fibrous scaffold design with biomimetic fibril hierarchy, toughening mechanisms, and loading capabilities for systematic tissue engineering applications.     

Real time TEM observation of alumina ceramic nano-particles during compression

The behavior of alumina nano-particles taken from a commercial powder is investigated during in situ compression experiments in a transmission electron microscope (TEM). Small particles of 40 nm in diameter can undergo severe plastic deformation without failure, whereas brittle fracture is observed for 120 nm sized nano-particles. This is evidence of a critical size under which alumina, at least in the form of nano-particles, cannot be considered as brittle materials even at room temperature and a direct observation of the grinding limit generally observed during ball milling.     

The role of eye movements in the missing-letter effect revisited with the rapid serial visual presentation procedure.

When participants read a text while searching for a target letter, they are more likely to miss the target letter embedded in frequent function words than in less frequent content words. This effect is usually observed with a text displayed normally, for which it has been found that frequent function words are fixated for a smaller amount of time than less frequent content words. However, similar pattern of omissions have been observed with a rapid serial visual presentation procedure in which words appear one at a time. These parallel results would demonstrate that fixation duration per se is not the proximal cause of the missing-letter effect only if eye movements are not made during the rapid serial visual presentation procedure. Therefore, the authors performed eye monitoring during the rapid serial visual presentation procedure. Results revealed that, with a rapid serial visual presentation procedure, participants fixated function and content words for almost the entire presentation duration. It is concluded that eye movements are not the proximal cause of the missing-letter effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of Two Homogalacturonan Pectins with Immunomodulatory Activity from Green Tea

Two natural homogalacturonan (HG) pectins (M_W ca. 20 kDa) were isolated from green tea based on their immunomodulatory activity. The crude tea polysaccharides (TPS1 and TPS2) were obtained from green tea leaves by hot water extraction and followed by 40% and 70% ethanol precipitation, respectively. Two homogenous water soluble polysaccharides (TPS1-2a and TPS1-2b) were obtained from TPS1 after purification with gel permeation, which gave a higher phagocytic effect than TPS2. A combination of composition, methylation and configuration analyses, as well as NMR (nuclear magnetic resonance) spectroscopy revealed that TPS1-2a and TPS1-2b were homogalacturonan (HG) pectins consisting of a backbone of 1,4-linked α-d-galacturonic acid (GalA) residues with 28.4% and 26.1% of carboxyl groups as methyl ester, respectively. The immunological assay results demonstrated that TPS1-2, which consisted mainly of HG pectins, showed phagocytosis-enhancing activity in HL-60 cells.     

P3HT : PCBM solar cells—The choice of source material

Bulk heterojunction solar cells based on P3HT : PCBM blend films are among the most intensively studied polymer solar cells. In spite of that, there is a huge variation of reported efficiencies in the literature, even for same device architectures and film preparation procedures. Here we investigated the influence of starting properties of P3HT and PCBM (different suppliers) on blend film morphology and device performance. We found that there was a strong dependence of the film morphology and device performance on the source of chemicals used. Both P3HT and PCBM affected the results, and higher nominal purity did not necessarily result in better device performance. The dependence of the film morphology and device performance on the properties of P3HT and PCBM is discussed in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39776.     

The role of interface modification on thermal degradation and crystallization behavior of composites from commingled polypropylene fiber and banana fiber

The thermal degradation behavior of banana fiber and polypropylene/banana fiber composites has been studied by thermogravimetric analysis. Banana fiber was found to be decomposing in two stages, first one around 320°C and the second one around 450°C. For chemically treated banana fiber, the decomposition process has been at a higher temperature, indicating thermal stability for the treated fiber. Activation energies for thermal degradation were estimated using Coats and Redfern method. Calorific value of the banana fiber was measured using a constant volume isothermal bomb calorimeter. Crystallization studies exhibited an increase in the crystallization temperature and crystallinity of polypropylene upon the addition of banana fiber. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

The Engineering of Bacteria Bearing Azido‐Pseudaminic Acid‐Modified Flagella

Catch a tiger by the tail : We have demonstrated that by feeding nonmotile mutant C. jejuni bacteria with a neutral azide‐labelled pseudaminic acid precursor we can restore their ability to generate functional flagella. The presence of azido‐pseudaminic acid on the surface of the flagella provides a bio‐orthogonal chemical handle that can be used to modify the flagellar proteins.