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In past decade, Pt-based nanomaterials as peroxidase mimics have attracted much attention for H2O2 and glucose detection. However, easy aggregation of Pt nanoparticles (Pt NPs) greatly decreases their peroxidase-like activity. In this work, novel Pt/EMT nanocomposites were prepared by uniformly loading Pt NPs (5?8 nm) onto the support of ultrasmall EMT zeolite (15?20 nm), a kind of low-silica microporous aluminosilicate material. The hybrid Pt/EMT nanomaterials could be well dispersed in water to form a homogeneous suspension, and were then utilized as a superior peroxidase-like catalyst for oxidation of 3,3?,5,5?-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). The optimal catalyst of 2.6Pt/EMT nanocomposite exhibited excellent catalytic performance toward H2O2 and TMB than natural enzyme of horseradish peroxidase (HRP) by using a steady-state kinetic analysis based on the typical Michaelis-Menten kinetics theory. The peroxidase-like catalyst showed a promising activity in a wide pH and temperature range as well as the long-term stability. A facile and reliable colorimetric assay based on the peroxidase mimic of Pt/EMT nanocomposite was constructed for precise detection of H2O2 and glucose in a wide linear range, with low limits of detection of 1.1 ?M and 13.2 ?M, respectively. Due to high selectivity to glucose against other sugars on the catalyst, the method was demonstrated to accurately measure the concentration of glucose in real samples including human blood serum and fruit juices, indicating a potential application of the Pt/EMT nanocomposites as a robust peroxidase mimic and a reliable biosensor in the fields of clinical diagnosis, pharmaceutical, food research and so on. 2020 Scopus

The solid surface characterization using contact angle measurement is complicated and time-consuming. In this work, two computational algorithms in MATLAB and C were developed and validated by the surface properties determination of talc filler (TCF) and colored talc filler (CTCF). The results indicated that, the surface free energy parameters calculated using the two algorithms for both samples were consistent. As compared to the MATLAB function, the assembly statements of C function were longer, although the unknowns can be directly obtained using this toolbox. The γ S D values determined by the Owens-Wendt-Kaelble (OWK), van Oss-Chaudhury-Good (vOCG) and Wu methods were consistent and contributed a major part of the γ S T . Compared to γ S D , the γ S SP component contributed less to γ S T , implying a lower polarity for both samples. The lower γ S D and γ S SP for CTCF added up to a lower γ S T value, which could reduce filler particle-particle interactions. The mechanical properties study of acrylonitrile-butadiene-styrene (ABS) matrix filled with the two fillers showed that the incorporation of them played mainly a reinforcing role, and a better performance for CTCF was observed.

The redox flow battery is one of the most promising grid-scale energy storage technologies that has the potential to enable the widespread adoption of renewable energies such as wind and solar. To do so, the performance of redox flow batteries must be enhanced while the cost needs to be reduced. Electrodes are a key component where coupled electrochemical reactions and mass transport take place, and they play a critical role in determining the battery performance and system cost. This review summarizes recent developments in the design and fabrication of electrospun carbon fibers, which offers a bottom-up solution to the formation of electrodes with desired properties for high-performance flow batteries. The principles of electrospinning nanofibers and the key parameters that affect the morphologies of electrospun carbon fibers are discussed and summarized. The factors that influence electrode properties, including geometric structures, surface properties, electrical conductivity, mechanical strength, and wettability on the battery performances, are comprehensively elaborated with an emphasis on the electrode structure and surface properties that determine the mass transport and reaction kinetics. Finally, the scientific challenges and prospects of electrospun carbon fiber electrodes with maximized specific surface areas and hydraulic permeability are presented. This review offers insights into the design and development of advanced electrodes for next-generation flow batteries in the application of renewable energy storage.

Summary Nature-inspired superamphiphilic surfaces have drawn tremendous attention owing to its extreme liquid-loving behaviors. Herein, a micro-organized nano-channel (Mo-Na) superamphiphilic anodic aluminum oxide (AAO) surface with long-lasting superamphiphilic property is prepared by a facile one-step anodization method with controllable temperature change. Analysis of dynamic wetting behaviors on superamphiphilic Mo-Na AAO surfaces for various liquids reveals that the spreading factor is in negative correlation with the surface tension and liquid polarity. Detailed observation of the three-phase contact line shows a micro-scale capillary film on superamphiphilic Mo-Na AAO surfaces, which results from the horizontal component of the capillary force. Taking advantage of the superamphiphilic property, water droplets can spread completely on these Mo-Na AAO surfaces within a short time, which can be applied for efficient heat dissipation. Moreover, the unique AAO surface with Mo-Na structures also offers an effective template for future efforts in AAO-based composite devices., Graphical abstract, Highlights • Discovery of micro-organized nano-channel superamphiphilic AAO structures • One-step anodization method to prepared long-lasting superamphiphilic AAO surfaces • Effective heat dissipation property based on the super-spreading behaviors, Biomimetics ; Materials Property ; Surface Property

Vehicle operation over paved and unpaved roads is an emission source that significantly contributes to air pollution. Emissions are derived from vehicle exhaust pipes and re-suspension of particulate matter generated by wind erosion and tire to road surface interactions. Environmental authorities require a methodology to evaluate road impact areas, which enable managers to initiate counter-measures, particularly under circumstances where historic meteorological and/or air quality data is unavailable. The present study describes an analytical and experimental work developed to establish a simplified methodology to estimate the area influenced by vehicular roads. AERMOD was chosen to model pollutant dispersion generated by two roads of common attributes (straight road over flat terrain) under the effects of several arbitrary chosen weather conditions. The resulting pollutant concentration vs. Distance curves collapsed into a single curve when concentration and distance were expressed as dimensionless numbers and this curve can be described by a beta distribution function. This result implied that average concentration at a given distance was proportional to emission intensity and that it showed minor sensitivity to meteorological conditions. Therefore, road influence was defined by the area adjacent to the road limited by distance at which the beta distribution function equaled the limiting value specified by the national air quality standard for the pollutant under consideration. © 2016 Elsevier Ltd

Novel methodology for facilely fabricating nanofiltration (NF) composite membrane has been successfully developed by employing nucleophilic nature of polydopamine (PDA) chemistry. The self-polymerized PDA coating over polysulfone (PSf) substrate was utilized as a key intermediate layer for trimesoyl chloride (TMC) grafting followed by poly(ethyleneimine) (PEI) deposition to construct the hierarchically structured separation layer of NF membrane. In contrast to the electrophilic quinone moieties of PDA layer usually involved in the Michael addition and Schiff base reactions with polymeric amines for membrane preparation in previous reports, the phenolic hydroxyl groups of catechol moieties as well as amine groups at the PDA layer possess nucleophilic nature, which are capable of quickly coupling with the highly reactive acyl chlorides to form ester and amide bonds in the step of TMC grafting, resulting in TMC moieties covalently anchored at the PDA layer with free acyl chloride groups. Such created acyl chlorides are further coupled with the amine groups of branched PEI polymer in the PEI deposition procedure to form the stable amide bonds linking the PDA base layer and PEI upper layer in the resulting hierarchical separation layer. The properties of membranes prepared at different stages were characterized with respect to surface chemistry, pore properties, and separation performances to understand deeply the newly developed methodology for membrane preparation. Further studies focusing on NF properties and stability of the developed NF membrane revealed that such membrane shows high efficiencies in retention of divalent cations, small organic molecules as well as heavy metal ions, and exhibits desirable thermal stability and long-term performance stability. 2016 Elsevier B.V. This work is supported by Grant from the Qatar National Research Fund (QNRF) under its National Priorities Research Program (NPRP) award number NPRP 4-935-2-354 . The statements made herein are solely the responsibility of the authors. We acknowledge Gas Processing Center (GPC, Qatar University) for XPS measurements and Center of Advanced Materials (CAM, Qatar University) for AFM measurements. Scopus

PE/PPE proteins are involved in several processes during Mycobacterium tuberculosis (Mtb) infection of target cells; studying them is extremely interesting as they are the only ones from the Mycobacterium genus, they abound in pathogenic species such as Mtb and their function remains yet unknown. The PE9 protein (Rv1088) was characterised, the rv1088 gene was identified by PCR in Mtb complex strains and its expression and localisation on mycobacterial surface was confirmed by Western blot and immunoelectron microscopy. Bioinformatics tools were used for predicting PE9 protein structural aspects and experimental study involved the circular dichroism of synthetic peptides. The peptides were tested in binding assays involving U937 and A549 cells; two high activity binding peptides (HABPs) were found for both cell lines (39226-1MSYMIATPAALTAAATDIDGI21 and 39232-125YQRHFGTGGQPEFRQHSEHRR144), one for U937 (39231-104YAGAGRRQRRRRSGDGQWRLRQ124) and one for A549 (39230-83YGTGVFRRRRGRQTVTAAEHRA103). HABP 39232 inhibited mycobacterial entry to A549 cells (~70%) and U937 cells (~50%), peptides 39226 and 39231 inhibited entry to U937 cells (~60% and 80%, respectively) and peptide 39230 inhibited entry to A549 cells (~60%). This emphasised HABPs' functional importance in recognition between Mtb H37Rv and target cell receptors. These peptide sequences could be involved in invasion and were recognised by the host's immune system, thereby highlighting their use when designing an efficient anti-tuberculosis multiantigenic vaccine. © 2016 Elsevier B.V.

Electrospinning of polyacrylic acid (PAA) nanofibres (NF) incorporating β-cyclodextrin inclusion complex (β-CD-IC) of quercetin (QU) was performed. Here, β-CD was used as not only the crosslinking agent for PAA nanofibres but also as a host molecule for inclusion of QU. The phase solubility test showed enhanced solubility of QU due to the inclusion complexation; in addition, the stoichiometry of QU/β-CD-IC was determined to be 1:1. Computational modelling studies confirmed that 1:1 and 1:2 complex formation are desirable; 1:1 complex formation was chosen to have higher weight loading of QU. SEM images showed that PAA/QU/β-CD-IC-NF were bead-free and uniform. XRD indicated that PAA/QU/β-CD-IC-NF were amorphous in nature without the crystalline peaks of QU. Comparative results revealed that the release profile of QU from PAA/QU/β-CD-IC-NF was much slower but greater in total than from PAA/QU/β-CD-IC-film. Moreover, high antioxidant activity and photostability of QU was achieved in PAA/QU/β-CD-IC-NF. © 2015 Elsevier Ltd.

Summary Graphene materials (GMs) are being investigated for multiple microbiological applications because of their unique physicochemical characteristics including high electrical conductivity, large specific surface area, and robust mechanical strength. In the last decade, studies on the interaction of GMs with bacterial cells appear conflicting. On one side, GMs have been developed to promote the proliferation of electroactive bacteria on the surface of electrodes in bioelectrochemical systems or to accelerate interspecies electron transfer during anaerobic digestion. On the other side, GMs with antibacterial properties have been synthesized to prevent biofilm formation on membranes for water treatment, on medical equipment, and on tissue engineering scaffolds. In this review, we discuss the mechanisms and factors determining the positive or negative impact of GMs on bacteria. Furthermore, we examine the bacterial growth-promoting and antibacterial applications of GMs and debate their practicability., Graphical Abstract, Surface Property; Microbiology; Microbiofilms

Systems rich in terrigenous dissolved organic carbon (DOC), like the Rio Negro, can contribute significant amounts of carbon dioxide back to the atmosphere and support important microbial communities. We investigated photo-oxidation in the Rio Negro: (1) the depth to which light causes complete photo-oxidation to CO2 and changes in DOC structure, (2) the daily rate of change of absorbance indices, (3) the relationship between sub-surface rates of photo-oxidation to CO2 and light exposure, (4) the areal rates of photo-oxidation, and (5) the stability of fluorophore signals. Experiments were run in an outdoor pool of Rio Negro water, under natural sunlight during the dry seasons of 2015 and 2018. In 2018, rates of complete photo-oxidation and changes in absorbance indices decayed exponentially, approaching their asymptotes between 9 and 15 cm depth. In 2015, direct absorbance indices ceased changing at 14 cm depth. Fluorescence of humic acid-like moieties continued to decrease, sometimes to 35–43 cm depth. This indicates that partial photo-oxidation of DOC, and thus interaction with the microbial community, occurs to greater depths than previously expected. Areal rates of CO2 production were 28.8 and 39.3 mg C m−2 d−1 (two experiments, October 2018). Sub-surface (1.1 cm) rates were strongly related to light levels, reaching a maximum of 0.68 mg C l−1 d−1 in September. Complete photo-oxidation ceased below 29.6 mW cm−2 d−1 UV radiation, providing a daily baseline for observable production of CO2. Absorbance indices changed by 9 to 14% d−1 at high light levels, except for R254/365 (4.4% d−1). Fluorophore emission ranges were stable between 2014 and 2018, indicating that emissions can be compared across time and space. This study contributes to better estimates and understanding of photo-oxidation in tropical, black-water rivers, which will be useful for carbon modelling. © 2020 Elsevier B.V.

Deposition of fly ash particles onto heat-transfer surfaces is often one of the reasons for unscheduled shut-downs of coal-fired boilers. Fouling deposits encountered in convective sections of a boiler are characterized by arrival of ash particles in solidified (solid) state. Fouling is most frequently caused by condensation and chemical reaction of alkali vapors with the deposited ash particles creating a wet surface conducive to collect impacting ash particles. Hence, the amount of alkali elements present in coals, which, in turn, is available in the flue gas as condensable vapors, determines the formation and growth of fouling deposits. In this context, removal of alkali elements becomes vital when inferior coals having high-ash content are utilized for power generation. With the concept of reducing alkali elements present in a coal entering the combustor, whereby the fouling deposits can either be minimized or be weakened due to absence of alkali gluing effect, the ultrasonic leaching of alkali elements from coals is investigated in this study. Ultrasonic water-washing and chemical-washing, in comparison with agitation, are studied in order to estimate the intensification of the alkali removal process by sonication. � 2015 Elsevier B.V. All rights reserved.

Electrostatic precipitator (ESP) is an electrohydrodynamic-based air filter that charges particles based on corona discharge and collects particles by induced electrostatic forces. Inducing corona discharge requires strong electric fields that, however, bring reliability issues because of oxidation. This paper presents the characteristics of an ESP that uses the cylindrical corona electrodes whose longitudinal axis is perpendicular to the surface of the ground electrode. The characteristics include the current-voltage curve, the surface oxidation of the cylindrical corona electrodes, and the element analysis. The characteristics are presented with respect to the pitch and diameter of the cylindrical corona electrodes. The results show that the characteristics mentioned above can correlate to the electric fields around the cylindrical corona electrodes. Stronger electric field around the cylindrical corona electrode results in higher collection efficiency, more oxidation on the cylindrical corona electrode, and shorter life of the cylindrical corona electrode., Electrical engineering; Electrical systems reliability; Plasma physics; Surface property; Electrical property; Air quality; Electrostatic precipitator; Cylinder electrode; Corona discharge; Oxidation

WOS: 000343613000026 PubMed ID: 25256476 We report on a facile and robust method by which surface of electrospun cellulose acetate (CA) nanofibers can be chemically modified with cationic polymer brushes for DNA adsorption. The surface of CA nanofibers was functionalized by growing poly[(ar-vinylbenzyl)trimethylammonium chloride)] [poly(VBTAC)] brushes through a multi-step chemical sequence that ensures retention of mechanically robust nanofibers. Initially, the surface of the CA nanofibers was modified with RAFT chain transfer agent. Poly(VBTAC) brushes were then prepared via RAFT-mediated polymerization from the nanofiber surface. DNA adsorption capacity of CA nanofibrous web surface functionalized with cationic poly(VBTAC) brushes was demonstrated. The reusability of these webs was investigated by measuring the adsorption capacity for target DNA in a cyclic manner. In brief, CA nanofibers surface-modified with cationic polymer brushes can be suitable as membrane materials for filtration, purification, and/or separation processes for DNA. (C) 2014 Elsevier Ltd. All rights reserved. EU FP7-PEOPLE-RG Marie Curie-IRG (NANOWEB) [PIRG06-GA-2009-256428]; Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP); TUBITAK-BIDEB Dr T. Uyar acknowledges EU FP7-PEOPLE-2009-RG Marie Curie-IRG (NANOWEB, PIRG06-GA-2009-256428) and The Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP) for partial funding. A. Celebioglu acknowledges TUBITAK-BIDEB for the national PhD study scholarship.

Glossiness is the visual appearance of an object's surface as defined by its surface reflectance properties. Despite its ecological importance, little is known about the neural substrates underlying its perception. In this study, we performed the first human neuroimaging experiments that directly investigated where the processing of glossiness resides in the visual cortex. First, we investigated the cortical regions that were more activated by observing high glossiness compared with low glossiness, where the effects of simple luminance and luminance contrast were dissociated by controlling the illumination conditions (Experiment 1). As cortical regions that may be related to the processing of glossiness, V2, V3, hV4, VO-1, VO-2, collateral sulcus (CoS), LO-1, and V3A/B were identified, which also showed significant correlation with the perceived level of glossiness. This result is consistent with the recent monkey studies that identified selective neural response to glossiness in the ventral visual pathway, except for V3A/B in the dorsal visual pathway, whose involvement in the processing of glossiness could be specific to the human visual system. Second, we investigated the cortical regions that were modulated by selective attention to glossiness (Experiment 2). The visual areas that showed higher activation to attention to glossiness than that to either form or orientation were identified as right hV4, right VO-2, and right V3A/B, which were commonly identified in Experiment 1. The results indicate that these commonly identified visual areas in the human visual cortex may play important roles in glossiness perception.

The shape of a drop on an inclined hysteretic surface has been studied both theoretically and experimentally in this paper. Surface Evolver (SE) has been used to model the shape of the drop. The triple line was initially circular. The energy minimization method from SE is coupled with a triple line dynamics model to incorporate contact angle hysteresis (CAH) into the simulations. Experiments have also been performed with sessile drops on tilting surfaces to validate the results obtained from the SE model. From this study, two critical inclination angles are identified that describe the incipient motion of the drop. The moving angle is the first critical inclination angle at which the triple line is on the verge of being deformed from a given initial shape. The sliding angle is the second critical inclination angle at which the entire drop is in a state of impending motion. It was observed that the moving angle is a strong function of the initial contact angle. It was observed to increase initially and then decrease as the initial contact angle is increased. The sliding angle decreased monotonically as the initial contact angle is increased. A quantitative correlation is developed to explain the sliding angle as a function of the initial conditions. The predictions of this correlation have been shown to compare well with the experimental data from this study as well as with the literature. � 2014 Elsevier B.V.

The objective of this study is to prepare polymeric surfaces which will adsorb L1210 leukemia cells selectively more than that of healthy human leukocytes in order to develop new treatment options for people with leukemia. Chemically heterogeneous and micropatterned surfaces were formed on round glass slides by dip coating with accompanying phase-separation process where only commercial polymers were used. Surface properties were determined by using optical microscopy, 3D profilometry, SEM and measuring contact angles. Polymer, solvent/nonsolvent types, blend composition and temperature were found to be effective in controlling the dimensions of surface microislands. MTT tests were applied for cell viability performance of these surfaces. Polystyrene/polyethylene-polypropylene blend surfaces were found to show considerable positive selectivity to L1210 leukemia cells where L1210/healthy leukocytes adsorption ratio approached to 9-fold in vitro. Effects of wettability, surface free energy, microisland size geometry on the adsorption performances of L1210/leukocytes pairs are discussed. © 2013 Elsevier B.V.

Laser-engineered net shaping (LENS�), a commercial additive manufacturing process, was used to modify the surfaces of 316 L stainless steel with bioactive hydroxyapatite (HAP). The modified surfaces were characterized in terms of their microstructure, hardness and apatite forming ability. The results showed that with increase in laser energy input from 32 J/mm2 to 59 J/mm2 the thickness of the modified surface increased from 222 � 12 ?m to 355�6 ?m, while the average surface hardness decreased marginally from 403 � 18 HV0.3 to 372 � 8 HV0.3. Microstructural studies showed that the modified surface consisted of austenite dendrites with HAP and some reaction products primarily occurring in the inter-dendritic regions. Finally, the surface-modified 316 L samples immersed in simulated body fluids showed significantly higher apatite precipitation compared to unmodified 316 L samples. � 2013 Elsevier B.V. All rights reserved.

The morphology of fibers synthesized through electrospinning has been found to mimic extracellular matrix. Coaxially electrospun fibers of gelatin (sheath) coated poly (3-hydroxybutyric acid) (PHB) (core) was developed using 2,2,2 trifluoroethanol(TFE) and 1,1,1,3,3,3 hexafluoro-2-propanol(HFIP) as solvents respectively. The coaxial structure and coating of gelatin with PHB fibers was confirmed through transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Thermal stability of the coaxially electrospun fibers was analyzed using thermogravimetric analysis(TGA), differential scanning calorimetry(DSC) and differential thermogravimetric analysis(DTA). Complete evaporation of solvent and gelatin grafting over PHB fibers was confirmed through attenuated total reflection-Fourier transformed infrared spectroscopy (ATR-FTIR). The coaxially electrospun fibers exhibited competent tensile properties for skin regeneration with high surface area and porosity. In vitro degradation studies proved the stability of fibers and its potential applications in tissue engineering. The fibers supported the growth of human dermal fibroblasts and keratinocytes with normal morphology indicating its potential as a scaffold for skin regeneration. � 2013 Elsevier B.V.

A procedure to control W(111) tip shape during etching to a single atom is described. It is demonstrated that the base of a single atom tip (SAT) can be shaped in order to alter the final operating voltage and emission opening angle of single atom tips for use as gas field ion sources or electron cold field emission sources. The operating voltages for single atom tips varied between 5 and 17 kV during helium ion beam generation. The emission properties of SATs were evaluated by fitting SAT images and measuring the full width at half maximum (FWHM) of the helium ion images. The FWHM is related to the linear opening angle and was evaluated as a function of SAT operating voltage. The results show that a forward focussing effect is observed such that the spot size decreases faster than is expected solely from an acceleration effect, indicating an affect from the tip shape. These results have consequences in designing gas field ion sources where etching is used to prepare the emitter.

This study is devoted to the natural vortex length which is one of the most important parameters for the performance of a reversed flow cyclone separator. A mathematical model was developed to estimate the natural vortex length and was applied to a newly designed cyclone which has a cylindrical body with sudden enlargement instead of a conical part. Special attention was given to the effects of inlet gas velocity, diameter and insertion length of the vortex finder and length of the frictional surface. A number of tests were also performed and the experimental data were compared with the model results. Experimental and model results show that, compared to the influence of the other parameters, the height of the frictional surface and inlet velocity affect the natural vortex length considerably. It was also observed that the vortex length increases up to a certain point with increasing the diameter of the vortex finder and then decreases after that. The results also showed that the present model is more successful in predicting the vortex length than the other models reported in the literature. (C) 2012 Elsevier B.V. All rights reserved.

Numerous samples of magnetite@silica and magnetite@silica@silane core-shell nanoparticles, previously used as prodrugs, were prepared by an experienced chemist, using the same identical equipment and the same lots of reagents. Their surface analyses showed batch-to-batch chemical variations: no two batches were found to have the same surface chemistries, showing unexpected Si-O bond scission and amine oxidation. Because the preparations used reactions recognized to be mild, and bond scission and oxidation were never previously reported for similar reactions on larger surfaces, the Fe3O4 nanoparticles that form the nanoparticle core appear to have acted as catalysts for these side reactions. The intended use of these nanoparticles, as drug carriers, is discussed in terms of cytotoxicological and biomedical consequences. © 2012 Elsevier Inc.

This study demonstrates that octacalcium phosphate (OCP) is a suitable substrate for alendronate local action towards bone cells. The results of the structural, spectroscopic, and microscopic investigation show that soaking OCP into alendronate solutions provoked the deposition of long crystalline rod-shaped formations, most likely a calcium alendronate complex, onto the calcium phosphate. The amount of alendronate loaded onto OCP increased as a function of the bisphosphonate concentration in solution. Osteoblast and osteoclast response was tested in single and in co-cultures on OCP containing 6.4 wt.% AL (OCP-AL), and for comparison on hydroxyapatite (HA) containing a similar amount (5.9 wt.%) of AL (HA-AL), as well as on pure OCP and HA as reference materials. Alendronate loaded materials displayed a beneficial effect on osteoblast activity and differentiation, whereas they inhibited osteoclast proliferation and differentiation. Crosstalking between osteoblast-like MG63 cells and human osteoclasts enhanced their response to alendronate. Moreover. OCP displayed a greater stimulating effect than HA on osteoblast differentiation, and AL promotion of osteoblast differentiation and mineralization was enhanced in OCP-AL with respect to HA-AL. (C) 2012 Elsevier Inc. All rights reserved.

Carrier microencapsulation, CME, is a technique to form a thin layer of metal oxide or hydroxide on pyrite surface using a water soluble organic carrier combined with metal ions. The present study investigated the effect of CME using a tris-catecholato complex of Si 4+ , Si(cat) 3 2− on pyrite-coal separation by dynamic bubble pick-up experiments and Hallimond tube flotation experiments using coal, pyrite, and a coal–pyrite mixture. The mineral samples were treated in 0–5 mol m − 3 Si(cat) 3 2− solutions at pH 4–9 at treatment times of 1–24 h. Dynamic bubble pick-up experiments showed that CME treatment converted the pyrite surface from hydrophobic to hydrophilic but did not affect coal's hydrophobic surface. The results of the Hallimond tube flotation experiments of a coal–pyrite mixture at pH 7–9 in the presence of kerosene as a collector showed that pyrite floatability was selectively suppressed after 1 h CME treatment with 0.5 mol − 3 Si(cat) 3 2− while both coal and pyrite were floated without the treatment. This indicates that CME treatment is effective in suppressing pyrite floatability in coal–pyrite flotation.

Pulmonary surfactant is a complex lipid-protein mixture whose main function is to reduce the surface tension at the air-liquid interface of alveoli to minimize the work of breathing. The exact mechanism by which surfactant monolayers and multilayers are formed and how they lower surface tension to very low values during lateral compression remains uncertain. We used time-of-flight secondary ion mass spectrometry to study the lateral organization of lipids and peptide in surfactant preparations ranging in complexity. We show that we can successfully determine the location of phospholipids, cholesterol and a peptide in surfactant Langmuir-Blodgett films and we can determine the effect of cholesterol and peptide addition. A thorough understanding of the lateral organization of PS interfacial films will aid in our understanding of the role of each component as well as different lipid-lipid and lipid-protein interactions. This may further our understanding of pulmonary surfactant function. © 2010 Elsevier B.V. All rights reserved.

Regeneration of the activity of three-way catalytic converters (TWCs) was tested for the first time using a biodegradable metal chelating agent (S, S-ethylenediamine disuccinic acid (S, S-EDDS). The efficiency of this novel environmentally friendly solvent in removing various contaminants such as P, Zn, Pb, Cu and S from commercial aged three-way catalysts, and improving their catalytic performance towards CO and NO pollutants removal has been investigated. Four samples of catalysts from the front and rear inlets of two different TWCs with different mileages and aged under completely different driving conditions were investigated. The catalysts were characterized using various techniques, such as X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area measurements (N2 adsorption at 77K). Quantitative ICP-MS analyses and SEM-EDS studies show the removal of Zn, P and Pb. SEM-EDS images obtained at low magnification (50μm) showed considerable differences in the surface morphology and composition after washing with S, S-EDDS. However, XRD studies indicated neither little to no removal of major contaminant compound phases nor major structural changes due to washing. Correspondingly, little or no enhancement in BET surface area was observed between the used and washed samples. Light-off curves show that the regeneration procedure employed can effectively improve the catalytic performance towards NO pollutant. © 2010 Elsevier B.V. 186 2-3 999 1006 Cited By :25

Direct hapten-linked multiplexed immunoassay is developed on the polycarbonate surface of standard Digital Versatile Discs (DVDs) for six compounds of environmental concern, as proof of concept. Carboxylated haptens are directly linked to the aminated polycarbonate surface through carbodiimide/succinimide coupling. The modified DVD surface maintained its physical and optical properties. Multiplexed assay reached detection limits down to 0.1¿g/L for chlorpyrifos, 2,4,5-trichlorophenoxypropionic acid, sulfathiazole and sulfasalazine and down to 1.0¿g/L for fenthion and malathion. This approach presents advantages such as the improvement in sensitivity in comparison to protein-hapten conjugate format for all the studied analytes and the absence of cross-interference effects, allowing high throughput multianalysis on the same surface. Also, a comparison of the performance of two sensing strategies indicated that DVD disc and drive approach turned out in a simpler mode, the assays being more reproducible and with higher signal to noise ratios. © 2010 Elsevier B.V., This research was funded through FEDER projects CTQ2007-64735/BQU (CICYT, Spain) and ACOMPGVA-2009/650 (GVA, Spain). The Spanish MEC provided J.T.-L. with a grant for his PhD studies.

A new definition of the activity of surface sites on lactose carriers for dry powder inhalation is proposed which relates to drug detachment during dispersion. The new definition is expected to improve the understanding of 'carrier surface site activity', which stimulates the unambiguous communication about this subject and may aid in the rational design and interpretation of future formulation studies. In contrast to the currently prevailing view on carrier surface site activity, it follows from the newly proposed definition that carrier surface site activity depends on more variables than just the physicochemical properties of the carrier surface. Because the term 'active sites' is ambiguous, it is recommended to use the term 'highly active sites' instead to denote carrier surface sites with a relatively high activity. © 2014 Elsevier B.V. All rights reserved.

Cell rolling on the vascular endothelium plays an important role in trafficking of leukocytes, stem cells, and cancer cells. We describe a semianalytical model of cell rolling that focuses on the microvillus as the unit of cell-substrate interaction and integrates microvillus mechanics, receptor clustering, force-dependent receptor-ligand kinetics, and cortical tension that enables incorporation of cell body deformation. Using parameters obtained from independent experiments, the model showed excellent agreement with experimental studies of neutrophil rolling on P-selectin and predicted different regimes of cell rolling, including spreading of the cells on the substrate under high shear. The cortical tension affected the cell-surface contact area and influenced the rolling velocity, and modulated the dependence of rolling velocity on microvillus stiffness. Moreover, at the same shear stress, microvilli of cells with higher cortical tension carried a greater load compared to those with lower cortical tension. We also used the model to obtain a scaling dependence of the contact radius and cell rolling velocity under different conditions of shear stress, cortical tension, and ligand density. This model advances theoretical understanding of cell rolling by incorporating cortical tension and microvillus extension into a versatile, semianalytical framework. � 2010 by the Biophysical Society.

Nanofiber poly(?-caprolactone) (PCL) scaffolds were fabricated by electrospinning, and their ability to enhance the osteoblastic behavior of marrow stromal cells (MSCs) in osteogenic media was investigated. MSCs were isolated from Wistar rats and cultured on nanofiber scaffolds to assess short-term cytocompatibility and long-term phenotypic behavior. Smooth PCL substrates were used as control surfaces. The short-term cytocompatibility results indicated that nanofiber scaffolds supported greater cell adhesion and viability compared with control surfaces. In osteogenic conditions, MSCs cultured on nanofiber scaffolds also displayed increased levels of alkaline phosphatase activity for 3 weeks of culture. Calcium phosphate mineralization was substantially accelerated on nanofiber scaffolds compared to control surfaces as indicated through von Kossa and calcium staining, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Increased levels of intra- and extracellular levels of osteocalcin and osteopontin were observed on nanofiber scaffolds using immunofluorescence techniques after 3 weeks of culture. These results demonstrate the enhanced tissue regeneration property of nanofiber scaffolds, which may be of potential use for engineering osteogenic scaffolds for orthopedic applications. � 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The novel ligand 1-(2,4,6-trimethylbenzyl)-2-(2'-pyridyl)benzimidazole and its heteroleptic ruthenium (II) complex were synthesized. The complex was characterized using spectroscopic methods and cyclic voltammetry. Charge-separation was investigated within nanoporous titanium dioxide employing surface photovoltage spectroscopy. The performance of the ruthenium complex as a charge transfer photosensitizer in nanocrystalline, titanium dioxide-based, dye sensitized solar cells was studied under standard AM 1.5 sunlight using an electrolyte consisting of 0.6 M 1-butyl-3-methyl-imidazolium iodide, 0.1 M lithium iodide, 0.05 M iodine and 0.5 M 4-tert-butyl pyridine in 3-methoxy propyonitrile. The novel complex had a photocurrent density of 9.47 mA cm -2 , 600 mV open circuit potential and 0.60 fill factor yielding an efficiency of 3.4%. The photovoltaic performance of the colorant was compared with that of cis-bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato) (2,2'-bipyridyl-4,4'-di-nonyl) ruthenium(II); both compounds exhibited similar efficiency, while the fill factor value was higher for the novel dye. © 2009 Elsevier Ltd. All rights reserved.

Unfolding of proteins has often been mentioned as an important factor during the adsorption process at air-water interfaces and in the increase of surface pressure at later stages of the adsorption process. This work focuses on the question whether the folding state of the adsorbed protein depends on the rate of adsorption to the interface, which can be controlled by bulk concentration. Therefore, the adsorption of proteins with varying structural stabilities at several protein concentrations was studied using ellipsometry and surface tensiometry. For β-lactoglobulin the adsorbed amount (Γ) needed to reach a certain surface pressure (Π) decreased with decreasing bulk concentration. Ovalbumin showed no such dependence. To verify whether this difference in behavior is caused by the difference in structural stability, similar experiments were performed with cytochrome c and a destabilized variant of this protein. Both proteins showed identical Π - Γ, and no dependence on bulk concentration. From this work it was concluded that unfolding will only take place if the kinetics of adsorption is similar or slower than the kinetics of unfolding. The latter depends on the activation energy of unfolding (which is in the order of 100-300 kJ/mol), rather than the free energy of unfolding (typically 10-50 kJ/mol). © 2006 Elsevier Inc. All rights reserved.

This study investigates the release mechanism of a hydrophilic drug (caffeine) from hydrophobic matrix tablets composed of starch acetate. Different particle size fractions of starch acetate were mixed with caffeine (22% V/V) to obtain various mixture organisations in the powder, as 14 well as in the final tablet. The organisation of powder mixtures was calculated by the carrier payload of starch acetate particles, while the pore size distributions in tablets were measured by mercury intrusion porosimetry. A carrier payload below I indicated the existence of a free starch acetate particle surface, while numbers greater than 1 pointed to a complete occupation of the starch acetate particle surface area by caffeine particles. The carrier payload calculations gave a good prediction for the existence of a starch acetate matrix in the tablet structures. Caffeine matrices in tablets compressed from the mixtures could be detected by mercury intrusion porosimetry measurements. The existence of different matrices, as well as different pore networks, determined the physical changes of the tablets and the release mechanism of caffeine during dissolution tests. When a tablet contained only a caffeine matrix, rapid tablet disintegration and immediate release of the total amount of caffeine occurred. A single matrix of starch acetate resulted in tablets that remained intact, although cracks were formed. The co-existence of matrices of both materials created surface erosion of the tablet. The caffeine release profiles of tablets that remained intact or showed erosion were fitted by an equation containing both diffusional and relaxational factors to describe the effect of tablet porosity on drug release. (c) 2005 Elsevier B.V. All rights reserved.

The apparent dehydration energies and surface potentials of diverse alkaline earth halides are computed employing a novel simulation methodology incorporating hydration numbers, ion pairing effects and random distribution of molecules. The progressive variation of the hydration numbers and hydrated radii are estimated. The significance of the formalism in rationalizing the trend in the variation of the solubility, lattice energy, etc. is indicated. ? 2004 Elsevier B.V. All rights reserved.

In an attempt to gain fundamental information about the role of P on the chemical deactivation of a three-way catalyst (TWC), P was deliberatively incorporated in CeO 2 and Ce 0.8Zr 0.2O 2 solid solution. XRD, Raman, XPS, and N 2 physisorption studies have indicated that monazite, a Ce(III) phosphate (CePO 4) solid phase, is located at the surface/subsurface region of both solids. Different experimental approaches were used to investigate the alteration by P incorporation of the redox chemistry of CeO 2 and Ce 0.8Zr 0.2O 2 solids that is relevant to the oxygen storage and release properties of the current commercial TWCs. In particular, H 2-TPR, dynamic OSC measurements using CO and H 2 pulses, 18O 2 temperature-programmed isotopic exchange (TPIE), and 18O 2 transient isothermal isotopic exchange have been used. These studies revealed that the amount of labile surface and bulk oxygen and the bulk oxygen diffusion rates are significantly reduced when the solids are contaminated with phosphorus. The monazite present in the surface and subsurface region of the solid is proposed to be responsible for these results. The reduction of Ce(IV) present in the CeO 2 and Ce 0.8Zr 0.2O 2 solids is also affected. Ce(III) in monazite is very stable and cannot be oxidized to Ce(IV). Therefore, it cannot participate in the redox Ce(IV)/Ce(III) couple needed for the reduction of Ce(IV). Moreover, the formation of bulk and surface O vacant sites needed for the O storage and release steps involved in the OSC process was also found to be affected. The results of the present work provide support to the hypothesis that formation of monazite is one of the main chemical deactivation mechanisms of real TWCs since CePO 4 was found in deactivated vehicle-aged TWCs. © 2004 Elsevier Inc. 226 2 443 456 Cited By :51

We have investigated the mobility of bromoform (CHBr3) and chloroform (CHCl3) on amorphous solid water and crystalline ice surfaces, by monitoring their adsorption and desorption behavior using temperature programmed desorption spectroscopy and reflection absorption infrared spectroscopy. Up to its desorption temperature, of 140 K, CHCl 3 does not diffuse over the crystalline ice surface, whereas CHBr3 is found to be mobile at temperatures as low as 85 K. The results demonstrate distinct differences between the surface mobility of structurally similar haloform molecules on crystalline ice surfaces, which may have implications to the halocarbon chemistry occurring on atmospheric ice particles. ? 2004 Elsevier B.V. All rights reserved.

The two-dimensional flow field in the vicinity of the interface between laminae of a solid oxidizer and solid fuel under steady-state conditions is solved for empirical inputs, taking into account the nonplanarity of the burning surfaces of the two laminae. The experimentally observed nonplanar burning surface under steady-state conditions is used to prescribe the upstream boundary conditions to the gas phase domain. The regression rate of the burning surface along the laminar interface, determined experimentally, is also used as an input. This decouples the condensed phase energy balance from the gas phase fluid dynamics, and assigns the distribution of surface temperature along the burning surface. The equation for two-dimensional energy conservation in the condensed phase is also solved, with the heat flux balance giving a boundary condition across the burning surface. A distribution of heat release rate is assumed in the gas phase, and the gas phase energy equation is solved iteratively with a convergence criterion set by the interfacial heat flux balance across the burning surface. This obviates the need for a knowledge of the chemical kinetic details of the gas phase flame. The goal is to determine a realistic distribution of heat release rate which satisfies the burning surface profile and its regression rate, measured for a laminar system of ammonium perchlorate and polymethyl methacrylate at pressures below the self-deflagration limit of the former. The results indicate lateral heat conduction in the condensed phase from the oxidizer lamina to the fuel lamina. The computed distribution of heat release rate in the gas phase indicates the need to include heat release near the surface, as well as farther downstream at typical stand-off distances for the flame. ? 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Surface and catalytic properties of Cu-Ce-O composite materials prepared by solution combustion method have been investigated. The materials are characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR) and electron paramagnetic resonance spectroscopy (EPR). The results of EPR and TPR show finely dispersed Cu 2+ species on ceria matrix with low copper content. The Cu 2+ species exists in the form of dimers and clusters which are not evident in XRD. In addition CuO is also present as small clusters which grow to larger size at higher Cu content. There is no evidence of CuO forming a solid solution with fluorite CeO 2 in combustion method. The Cu 2+ species mostly appear on surface rather than in the bulk. Hydrogen peroxide decomposition kinetics has been carried out on Cu-Ce-O composite materials to investigate the effect of crystalline and well-dispersed copper oxide phases on CeO 2. From kinetic results, the catalyst materials can be grouped into highly dispersed as well as crystalline CuO phases present on CeO 2 matrix. Two parallel compensating lines for dispersed and crystalline CuO phases on CeO 2 are observed in ln A versus E a plot indicating the compensation effect in H 2O 2 decomposition. This observation is consistent with XRD and EPR results. ? 2003 Elsevier Science B.V. All rights reserved.

Formation and structure of glycinin gels were studied in relation to protein conformation for two pH values and three ionic strengths. While at I = 0.03 the gels were found to be fine stranded, gel coarseness increased when the ionic strength was higher. At I = 0.03 finer gel network structures were formed at pH 3.8 than at pH 7.6, whereas for I = 0.2 and 0.5 the reverse was found. The observed differences in gel stiffness (rheological dynamical measurements) did not correspond to coarseness of the gels. It was found that the nature of the primary network particles was different at pH 7.6 compared to pH 3.8, since at pH 7.6 only 51-69% of total protein was incorporated in the gel network (predominantly basic polypeptides), while at pH 3.8 all protein was present in the network. The higher water holding capacities observed at pH 7.6 compared to pH 3.8 support the idea that at pH 7.6 the non-network protein resides in the pores. At all conditions studied denaturation coincides with the induction of β-sheet at a secondary level (IR measurements), and with gel formation (except for I = 0.03). The largest increase in gel stiffness did not take place directly after denaturation but during the cooling part of the temperature cycle used. This increase in gel stiffness could not be related to changes in secondary structure. © 2002 Elsevier Science Ltd. All rights reserved. Chemicals/CAS: glycinin, 9007-93-6

The combined effect of titanium dioxide and silver oxide on the in situ formation of biphasic calcium phosphate ceramics was investigated. Titania (5-20mol%) was mixed with pure hydroxyapatite (HA) or HA containing Ag2O (10-20mol%) and was heated to 900�C for 12h. The sintered samples were found to contain tricalcium phosphate (?-TCP) and other phases along with HA depending upon the amount as well as the type of the additives used as evidenced by X-ray powder diffraction (XRD) and fourier transform infrared (FT-IR) spectroscopic studies. Enhanced TCP formation with reduced impurity phases was observed with TiO2-Ag2O addition. In vitro solubility study in phosphate buffer at physiological conditions shows the resorbable nature of these materials. A functionally graded material (FGM) structure was formed by spreading TiO2-Ag2O mixture on the surface of the HA green compact and heating at 900�C. The FGM shows gradient structure of TCP and HA from the surface to the interior of the pellet in addition to titania and silver phases. Copyright (C) 2000 Elsevier Science Ltd.The combined effect of titanium dioxide and silver oxide on the in situ formation of biphasic calcium phosphate ceramics was investigated. Titania (5-20 mol%) was mixed with pure hydroxyapatite (HA) or HA containing Ag2O (10-20 mol%) and was heated to 900 �C for 12 h. The sintered samples were found to contain tricalcium phosphate (?-TCP) and other phases along with HA depending upon the amount as well as the type of the additives used as evidenced by X-ray powder diffraction (XRD) and fourier transform infrared (FT-IR) spectroscopic studies. Enhanced TCP formation with reduced impurity phases was observed with TiO2-Ag2O addition. In vitro solubility study in phosphate buffer at physiological conditions shows the resorbable nature of these materials. A functionally graded material (FGM) structure was formed by spreading TiO2-Ag2O mixture on the surface of the HA green compact and heating at 900 �C. The FGM shows gradient structure of TCP and HA from the surface to the interior of the pellet in addition to titania and silver phases.

Adsorption of 4,5-bis(benzoylthio)1,3-dithiol-2-thione (Bz 2 dmit) on silver surface has been studied by SERS technique. SERS spectrum of bz 2 dmit adsorbed on silver colloid obtained by using a dispersive Raman spectrometer with 514.5 nm excitation is found to contain only vibrational bands corresponding to the dmit group indicating that Bz 2 dmit undergoes decomposition on the silver surface to dmit 2− ion. FT-SERS spectra of Bz 2 dmit obtained with chemically deposited silver film substrates exposed to methanolic adsorbate solutions are found to vary with exposure times. Spectra obtained for shorter exposure times contain vibrational bands associated with dmit as well as benzoyl groups: however intensities of bands corresponding to benzoyl groups are found to diminish with increasing exposure times. Decomposition of Bz 2 dmit is found to be solely due to the surface induced reaction of adsorbed Bz 2 dmit molecules with solvent molecules.

Nano-hydroxyapatite (nHA) reinforced magnesium composite (Mg-nHA) was fabricated by friction stir processing (FSP). The effect of smaller grain size and the presence of nHA particles on controlling the degradation of magnesium were investigated. Grain refinement from 1500 ?m to 3.5 ?m was observed after FSP. In vitro bioactivity studies by immersing the samples in supersaturated simulated body fluid (SBF 5 �) indicate that the increased hydrophilicity and pronounced biomineralization are due to grain refinement and the presence of nHA in the composite respectively. Electrochemical test to assess the corrosion behavior also clearly showed the improved corrosion resistance due to grain refinement and enhanced biomineralization. Using MTT colorimetric assay, cytotoxicity study of the samples with rat skeletal muscle (L6) cells indicate marginal increase in cell viability of the FSP-Mg-nHA sample. The composite also showed good cell adhesion. � 2014 Elsevier B.V.