72 results match your criteria: "University School of Chemical Technology[Affiliation]"

We present two facile approaches for introducing multivalent displays of tyrosine sulfate mimetic ligands on the surface of cellulose nanocrystals (CNCs) for application as viral inhibitors. We tested the efficacy of cellulose nanocrystals, prepared either from cotton fibers or Whatman filter paper, to inhibit alphavirus infectivity in Vero (B) cells. Cellulose nanocrystals were produced by sulfuric acid hydrolysis leading to nanocrystal surfaces decorated with anionic sulfate groups.

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Thermoresponsive xylan hydrogels via copper-catalyzed azide-alkyne cycloaddition.

Carbohydr Polym

February 2014

Department of Biotechnology and Chemical Technology, Aalto University School of Chemical Technology, Kemistintie 1, 02150 Espoo, Finland. Electronic address:

In the present work, hydrogels of birch wood xylan and thermoresponsive poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEG-PPG-PEG) were prepared using copper catalyzed alkyne-azide cycloaddition (CuAAC) in aqueous reaction conditions. First, reactive azide groups were introduced on the backbone of xylan by etherification of 1-azido-2,3-epoxypropane in alkaline water/isopropanol-mixture at ambient temperature, providing degree of substitution (DS) values up to 0.28.

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The structure and magnetic moment distribution are studied for an iron nanoparticle with varying degree of carbon adatom coverage. The limiting models of the study are the clean icosahedral Fe55 particle and the iron particle completely enclosed in carbon cages. Between the two extrema, partially covered particles are considered.

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Cellulose degradation in alkaline media upon acidic pretreatment and stabilisation.

Carbohydr Polym

January 2014

Department of Forest Products Technology, Aalto University School of Chemical Technology, P.O. Box 16300, Vuorimiehentie 1, Espoo, FI-00076 Aalto, Finland.

The present study reports on a revised kinetic model for alkaline degradation of cellulose accounting for primary peeling/stopping reactions as well as for alkaline hydrolysis followed by secondary peeling. Oxalic acid pretreated cotton linters was utilised as the model substrate for the prehydrolysis-soda anthraquinone process. The main emphasis was investigating the effect of end-group stabilising additives such as sodium borohydride (BH), anthraquinone (AQ), and anthraquinone-2-sulphonic acid sodium salt (AQS) on the rates of the yield loss reactions.

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Cellulosic substrates were modified by using sequential adsorption of functionalized carboxymethyl cellulose (CMC) and "click" chemistry in aqueous media. First, the effect of degree of substitution (DS), and level of functionalization as well as ionic strength of the medium were systematically investigated in situ by using quartz crystal microbalance with dissipation (QCM-D) in terms of the extent of adsorption of propargyl and azido functionalized CMC. It was found that the functionalization of CMC did not prevent its adsorption on cellulose.

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Adsorption of poly(ethylene glycol), hydrophobically end-capped with octadecenylsuccinic anhydride (OSA-PEG-OSA), on an ultrathin film of cellulose has been studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Normally, PEG does not adsorb on cellulosic surfaces, but the use of the telechelic hydrophobic modification was found to promote adsorption. The influence of the conformation of the polymer in solution prior to adsorption and the subsequent properties of the adsorbed layer were investigated.

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Single-walled carbon nanotubes (SWNTs) grown on rhodium (Rh) nanoparticles were demonstrated to have large chiral angles and a preference for metallic tubes.

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The effect of varying glucose, mannose and xylose concentrations on continuous solvent production at various dilution rates was studied by multiple linear regression (MLR) modeling using an immobilized column reactor. The factors affecting the solvent production were dilution rate and concentrations of glucose and mannose. MLR-models also showed a preference of glucose as well as its inhibitory effect on xylose consumption.

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Background And Objectives: A questionnaire study was carried out in collaboration with the European Blood Alliance (EBA) Tissues and Cells (T&C) working group. The aim was to assess the level of involvement and commonality of processes on the procurement, testing and storage of bone, corneas, umbilical cord blood (UCB) and haematopoietic stem cells (HSC) in order to identify different practices and to explore whether recommendations can be made for harmonization.

Materials And Methods: An online questionnaire was used for data collection in 2011, and 43 replies were received covering 71 product answers from 13 countries.

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Wood pulp as an immobilization matrix for the continuous production of isopropanol and butanol.

J Ind Microbiol Biotechnol

February 2013

Department of Biotechnology and Chemical Technology, Aalto University School of Chemical Technology, POB 16100, 00076 Aalto, Finland.

The study was focused on developing a continuous method to produce an alcohol mixture suitable to be used as a gasoline supplement. The immobilized column reactor with wood pulp fibers was successfully used for the continuous production of butanol and isopropanol using Clostridium beijerinckii DSM 6423. A sugar mixture (glucose, mannose, galactose, arabinose and xylose) representing lignocellulose hydrolysate was used as a substrate for the production of solvents.

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Zero-quantum filtered pure shift TOCSY.

Chem Commun (Camb)

January 2013

Department of Chemistry, Aalto University School of Chemical Technology, P.O. Box 16100, 00076, Finland.

The high spectral resolution provided by the pure shift TOCSY experiment can be significantly improved by zero-quantum filtering which eliminates dispersive anti-phase contributions from the spectrum.

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Network formation of nanofibrillated cellulose in solution blended poly(methyl methacrylate) composites.

Carbohydr Polym

January 2013

Polymer Technology, Department of Biotechnology and Chemical Technology, Aalto University School of Chemical Technology, P.O. Box 16100, 00076 Aalto, Finland.

Composites of poly(methyl methacrylate) (PMMA) and nanofibrillated cellulose (NFC) were prepared by solution blending and further processed by injection and compression molding. To improve adhesion at the PMMA/NFC interface, the nanofibrils were covalently grafted with PMMA. Formation of a percolating nanofibril network was observed between 1 and 5 wt.

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Multiphase designer droplets for liquid-liquid extraction.

Adv Mater

December 2012

Department of Materials Science and Engineering, Aalto University School of Chemical Technology, Tietotie 3, 02150, Espoo, Finland.

Multiphase liquid droplets consisting of three connected but immiscible liquid phases are demonstrated. The droplets have designer geometries stabilized by surface energy patterns; aqueous phases prefer contact with hydrophilic surface while organic phases prefer contact with hydrophobic areas. The multiphase droplets are applied for liquid-liquid-liquid extraction.

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SO(2)-ethanol-water (SEW) lignocellulosic fractionation has the potential to overcome the present techno-economic barriers that hinder the commercial implementation of renewable transportation fuel production. In this study, SEW fractionation of spruce wood chips is examined for its ability to separate the main wood components, hemicelluloses, lignin, and cellulose, and the potential to recover SO(2) and ethanol from the spent fractionation liquid. Therefore, overall sulfur and carbohydrate mass balances are established.

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Diastereoselective synthesis of vicinal amino alcohols.

Org Biomol Chem

June 2012

Department of Chemistry, Aalto University School of Chemical Technology, P.O. Box 16100 (Kemistintie 1), FI-00076 Aalto, Finland.

The vicinal amino alcohol is a common motif in natural products and pharmaceuticals. Amino acids constitute a natural, inexpensive, and enantiopure choice of starting material for the synthesis of such functionalities. However, the matters concerning diastereoselectivity are not obvious.

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SO2-ethanol-water (SEW) spent liquor from spruce chips was successfully used for batch and continuous production of acetone, butanol and ethanol (ABE). Initially, batch experiments were performed using spent liquor to check the suitability for production of ABE. Maximum concentration of total ABE was found to be 8.

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The total operating costs of small-scale monoclonal antibody production were calculated for two different upstream options and general downstream procedure based on protein A chromatography. The upstream options were a spin-filter equipped stirred-tank bioreactor (STR) and a hollow fiber bioreactor (HFB). Both the bioreactors were operated in perfusion mode.

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Tailoring surface properties of paper using nanosized precipitated calcium carbonate particles.

ACS Appl Mater Interfaces

September 2011

Aalto University School of Chemical Technology, Department of Forest Products Technology, P.O. Box 16300, 00076 Aalto, Finland.

Pigment particles used in paper coatings are typically of micrometer size and consequently the thickness of the coatings is, even at its lowest, in micrometer scale. Progress in nanotechnology has given way to the development of nanosized materials to be used in coatings, yet their exploitation has not been studied to a great extent. This study examines utilization of nanosized precipitated calcium carbonate (nanoPCC) particles in nanoscale thin coating layers.

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C-reactive protein (CRP) was determined in the concentration range 0.01-10 mg L(-1) using hot electron induced electrochemiluminescence (HECL) with devices combining both working and counter electrodes and sample confinement on a single chip. The sample area on the electrodes was defined by a hydrophobic ring, which enabled dispensing the reagents and the analyte directly on the electrode.

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Runnability problems caused by suspended bacteria in water using industries, have, in contrast to biofilms, received little attention. We describe here that Pseudoxanthomonas taiwanensis, a wide-spread and abundant bacterium in paper machine water circuits, aggregated dispersions of wood extractives ("pitch") and resin acid, under conditions prevailing in machine water circuits (10(9) cfu ml(-1), pH 8, 45°C). The aggregates were large enough (up to 50 μm) so that they could be expected to clog wires and felts and to reduce dewatering of the fiber web.

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Quartz crystal microbalance with dissipation monitoring (QCM-D), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were used as the tools to study the adsorption of bacteria onto surfaces of silica and polystyrene coated with materials related to papermaking. Cationic polyelectrolytes used as fixatives and retention aids in paper industry were found to promote irreversible adsorption of the ubiquitous white water bacterium, Pseudoxanthomonas taiwanensis, onto model surfaces of cellulose (pH 8). The high charged low molecular weight polyelectrolyte, poly(diallyldimethyl) ammonium chloride (pDADMAC) adsorbed to silica surface as a flat and rigid layer, whereas the low charged cationic polyacryl amide (C-PAM) of high molecular weight adsorbed as a thick and loose layer.

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Batch studies were carried out for studying the adsorption behaviour of phenol and 4-nitrophenol on granular activated carbon from a basal salt medium (BSM) at pH approximately 7.1 and temperature approximately 30 degrees C. The literature review was done in order to review the information for comparison purposes on equilibrium models of phenol and 4-nitrophenol adsorption on activated carbon.

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