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91.
Jukka Niskanen Jun Shan Heikki Tenhu Hua Jiang Esko Kauppinen Violeta Barranco Fernando Picó Kirsi Yliniemi Kyösti Kontturi 《Colloid and polymer science》2010,288(5):543-553
Silver ions being less toxic than silver nanoparticles, a more safe material can be obtained to be used as antimicrobial coating.
This can be achieved by using thiol chemistry and covalently attach the silver nanoparticles in the coating. Our aim is to
produce a coating having antimicrobial properties of silver ions but with the silver nanoparticles firmly attached in the
coating. Here, we present a way to produce silver nanoparticles that can be used as a component in a coating or as such to
produce an antimicrobial coating. The silver nanoparticles presented here are stabilized by a copolymer (poly(butyl acrylate–methyl
methacrylate)) that is soft and has well-known good film-producing properties. The reversible addition-fragmentation chain
transfer radical polymerization technique used to prepare the polymers provides conveniently a thiol group for effective binding
of the silver nanoparticles to the polymers and thus to the coating. 相似文献
92.
Joda H Beni V Curnane D Katakis I Alakulppi N Partanen J Lind K Strömbom L O'Sullivan CK 《Analytical and bioanalytical chemistry》2012,403(3):807-819
Coeliac disease is an inflammation of the small intestine, occurring in genetically susceptible individuals triggered by the
ingestion of gluten. Human Leukocyte Antigens (HLA) DQ2 and DQ8 gene have been identified as key genetic factors in coeliac
disease as they are presented in almost 100 % of the patients. These genes are encoded by the combination of certain alleles
in the DQA and DQB region of chromosome 6. Specifically, DQA1*05:01 and DQB1*02:01 alleles for serologically defined leukocyte
antigen DQ2 cis, DQA1*05:05 and DQB1*02:02 for DQ2 trans and DQA1*03:01 and DQB1*03:02 alleles for the DQ8. Specific identification
of these alleles is a challenge due to the high number of alleles that have been identified so far: 46 in the DQA region and
160 in the DQB region (as of IMGT/HLA Database 10/2011 release). In the reported work, the development of a multiplex colorimetric
assay for the low to medium HLA typing of the DQ2 and DQ8 genes is presented. The optimisation of probe design and assay conditions,
performed by both surface plasmon resonance and enzyme-linked oligonucleotide assay, are reported. Finally, the performances
of the developed typing platform were validated by the analysis of real patient samples and HLA typing, compared with those
obtained using hospital based typing technology and an excellent correlation obtained. 相似文献
93.
Paajanen M Katainen J Pakarinen OH Foster AS Lahtinen J 《Journal of colloid and interface science》2006,304(2):518-523
The humidity present in ambient atmosphere affects the adhesion of small particles by causing capillary bridge formation between the particle and the surface. Even in moderate relative humidities this, usually attractive, force can have a significant effect on adhesion behaviour of micro and sub-micro particles. We have directly measured the pull-off forces of initially adhered oxide particles on oxide surfaces with atomic force microscope in controlled atmosphere with adjustable humidity. We demonstrate the effect of the surface roughness resulting in two different regions of capillary formation and the particle shape having a strong effect on the humidity dependency of adhesion. The experimental results are explained by theoretical framework. 相似文献
94.
Tervonen H Saunavaara J Ingman LP Jokisaari J 《The journal of physical chemistry. B》2006,110(33):16232-16238
(19)F single-quantum (SQC) and (19)F-(33)S heteronuclear multiple-quantum coherence (HMQC) NMR spectroscopy of sulfur hexafluoride (SF(6)) dissolved in thermotropic liquid crystals (TLCs) were used to investigate the properties of TLCs. On one hand, environmental effects on the NMR parameters of SF(6), (19)F nuclear shielding, (19)F-(33)S spin-spin coupling, secondary isotope effects of sulfur on (19)F shielding, and the self-diffusion coefficient in the direction of the external magnetic field were studied as well. The temperature dependence of the (19)F shielding of SF(6) in TLCs was modeled with a function that takes into account the properties of both TLC and SF(6). It appears that the TLC environment deforms the electronic system of SF(6) so that the (19)F shielding tensor becomes slightly anisotropic, with the anisotropy being from -0.5 to -1.4 ppm, depending upon the TLC solvent. On the contrary, no sign of residual dipolar coupling between (19)F and (33)S was found, meaning that the so-called deformational effects, which arise from the interaction between vibrational and reorientational motions of the molecule, on the geometry of the molecule are insignificant. Diffusion activation energies, E(a), were determined from the temperature dependence of the self-diffusion coefficients. In each TLC, E(a) increases when moving from an isotropic phase to a nematic phase. The spin-spin coupling constant, J((19)F,(33)S), increases by ca. 10 Hz when moving from the gas phase to TLC solutions. The secondary isotope shifts of (19)F shielding are practically independent of TLC solvent and temperature. For the first time, (19)F-(33)S heteronuclear multiple-quantum NMR spectra were recorded for SF(6) in the gas phase and in a liquid-crystalline solution. 相似文献
95.
Hydroxyl-group functional polylactones were prepared and converted to acid- terminated polyesters in a reaction with a series of alkenylsuccinic anhydrides containing 8, 12, or 18 carbons in their alkenyl chains. These polyester precursors were then linked into higher molecular weight poly(ester anhydrides) containing alkenyl moieties in their polyester blocks. The hydrolysis behaviour of the poly(ester anhydrides) was found to depend on the thermal properties of the polyester precursors. For poly(ester anhydrides) prepared from low molecular weight prepolymers with thermal transitions below 37 degrees C, the presence of hydrophobic alkenyl chains in the polyester precursors slowed the rate of weight loss. Poly(ester anhydrides) prepared from higher molecular weight prepolymers showed the opposite weight-loss behaviour; i.e., the crystallinity and thermal transitions of the alkenyl chain-containing poly(ester anhydrides) were low, and the weight loss was faster than for poly(ester anhydrides) without the alkenyl chains. The differences in length of the alkenyl chain, as such, had little effect on the hydrolysis behaviour and thermal properties of the poly(ester anhydrides). 相似文献
96.
97.
We consider questions related to quantizing complex valued functions defined on a locally compact topological group. In the case of bounded functions, we generalize R. Werner's approach to prove the characterization of the associated normal covariant quantization maps. 相似文献
98.
Summary. We introduce a new algebraic framework to derive discrete absorbing boundary conditions for the wave equation in the one-dimensional
case. The idea is to factor directly the discrete wave operator and then use one of the factors as boundary condition. We
also analyse the stability of the schemes obtained this way and perform numerical simulations to estimate their practical
value.
Received June 14, 1997 / Revised version received September 15, 1997 相似文献
99.
Paul Blomstedt Romain Gauriot Niina Viitala Tapani Reinikainen Jukka Corander 《Journal of Chemometrics》2014,28(1):52-59
Statistical comparison of oil samples is an integral part of oil spill identification, which deals with the process of linking an oil spill with its source of origin. In current practice, a frequentist hypothesis test is often used to evaluate evidence in support of a match between a spill and a source sample. As frequentist tests are only able to evaluate evidence against a hypothesis but not in support of it, we argue that this leads to unsound statistical reasoning. Moreover, currently only verbal conclusions on a very coarse scale can be made about the match between two samples, whereas a finer quantitative assessment would often be preferred. To address these issues, we propose a Bayesian predictive approach for evaluating the similarity between the chemical compositions of two oil samples. We derive the underlying statistical model from some basic assumptions on modeling assays in analytical chemistry, and to further facilitate and improve numerical evaluations, we develop analytical expressions for the key elements of Bayesian inference for this model. The approach is illustrated with both simulated and real data and is shown to have appealing properties in comparison with both standard frequentist and Bayesian approaches. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
100.
Abstract Aliphatic polyesters, such as poly(lactic acids), need high molecular weight for acceptable mechanical properties. This can be achieved through ring-opening polymerization of lactides. The lactide route is, however, relatively complicated, and alternative polymerization routes are of interest. In this paper we report the properties of a polymer made by a two-step process: first a condensation polymerization of lactic acid and then an increase of the molecular weight with diisocyanate. The end product is then a thermoplastic poly(ester-urethane). The hydroxylterminated prepolymer was made with condensation polymerization of L–lactic acid and a small amount of 1,4-butanediol. The polymerization was performed in the melt under nitrogen and reduced pressure. The preparation of poly(ester-urethane) was done in the melt using aliphatic diisocyanates as the chain extenders reacting with the end groups of the prepolymer. The polymer samples were carefully characterized, including preliminary degradation studies. The results indicate that this route to convert lactic acid into thermoplastic biodegradable polymer has high potential. Lactic acid is converted into a mechanically attractive polymer with high yield, which could make the polymer suitable for high volume applications. The mechanical properties of the poly(ester-urethane) are comparable with those of poly(lactides). Capillary rheometer measurements indicate that the polymer is processible both by injection molding and extrusion. 相似文献