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351.
Development of a simple method for preparation of stable open tubular (OT) columns for proteins separation by capillary electrochromatography is still challenging. In this work, the titanium oxide (TiO2) nanoparticles coated OT column was successfully prepared for separation of proteins by capillary electrochromatography. The polydopamine (PDA) film was first formed in the inner surface of a fused-silica capillary by the self-polymerization of dopamine under alkaline conditions. Then the TiO2 coating was deposited onto the surface of pre-modified capillary with PDA by a liquid phase deposition process. The plentifully active hydroxyl groups in PDA coating can chelate with Ti4+ to boost the nucleation and growth of TiO2 film. The as-prepared TiO2 coated OT column was characterized by scanning electron microscopy and measurement of electroosmotic flow. Furthermore, the influence of liquid phase deposition time on the TiO2 coating was investigated. The TiO2 coated OT column was used for successful separation of two variants of β-lactoglobulin and eight glycoisoforms of ovalbumin. The column demonstrated good repeatability and stability. The relative standard deviations of migration times of proteins representing run-to-run, day-to-day, and column-to-column were less than 3.7%. Moreover, the application of the column was verified by successful separation of acidic proteins in egg white. 相似文献
352.
353.
《Arthropod Structure & Development》2017,46(1):116-129
The cuticle of arthropods is usually composed of layers of a chitin-protein-microcomposite, a proteinaceous epicuticle and a thin lipid coating. However, in some instances a thick cement layer (cerotegument) covers the cuticle and may produce elaborate microstructures. This has previously been described for millipedes and mites. Here we report the previously unknown presence of a superhydrophobic cerotegument in whip-spiders (Ambypygi) and reveal its variation in ultrastructure and water-repellence between species. We discuss the relevance of found micro-morphological and physical characters for taxonomy and phylogenetics of this group, and the potential biological functions. 相似文献
354.
Linda M. Gustafsson Pål Börjesson 《The International Journal of Life Cycle Assessment》2007,12(3):151-159
Background, Aims and Scope Using renewable feedstock and introducing biocatalysts in the chemical industry have been suggested as the key strategies
to reduce the environmental impact of chemicals. The Swedish interdisciplinary programme ‘Greenchem’, is aiming to develop
these strategies. One target group of chemicals for Greenchem are wax esters which can be used in wood surface coatings for
wood furniture, etc. The aim of this study was to conduct a life cycle assessment of four different wood surface coatings,
two wax-based coatings and two lacquers using ultra violet light for hardening (UV lacquers). One of the two wax-based coatings
is based on a renewable wax ester produced with biocatalysts from rapeseed oil, denoted ‘green wax’, while the other is based
on fossil feedstock and is denoted ‘fossil wax’. The two UV lacquers consist of one ‘100% UV’ coating and one ‘water-based
UV’ coating. The scope was to compare the environmental performance of the new ‘green’ coating with the three coatings which
are on the market today.
Methods The study has a cradle-to-grave perspective and the functional unit is ‘decoration and protection of 1 m2 wood table surface for 20 years’. Extensive data collection and calculations have been performed for the two wax-based coatings,
whereas mainly existing LCI data have been used to characterise the production of the two UV lacquers.
Results For all impact categories studied, the ‘100% UV’ lacquer is the most environmentally benign alternative. The ‘water-based
UV’ is the second best alternative for all impact categories except EP, where the ‘fossil wax’ is slightly better. For GWP
the ‘fossil wax’ has the highest contribution followed by the ‘green wax’. For AP and EP it is the ‘green wax’ that makes
the highest environmental impact due to the contribution from the cultivation of the rapeseed and the production of the rapeseed
oil. For POCP the ‘fossil wax’ makes the highest contribution, slightly higher than the contribution from the ‘green wax’.
Also the energy requirements for the ‘100% UV’ lacquer is much lower than for the other coatings. The results from the toxicological
evaluation conducted in this study, which was restricted to include only the UV lacquers, are inconclusive, giving different
results depending on the model chosen, EDIP97 or USES.
Discussion The result in this study shows that the environmental benefits of using revewable feedstock and processes based on biocatalysis
in the production of wax esters used in wood surface coatings are rather limited. This is due to the high environmental impact
from other steps in the life cycle of the coating.
Conclusions Overall the ‘100% UV’ lacquer seems to be the best alternative from an environmental point of view. This study shows that
the hot spots of the life cycle of the coatings are the production of the ingredients, but also the application and drying
of the coatings. The toxicity assessment shows the need for the development of a new model, a model which finds common ground
in order to overcome the current situation of diverging results of toxicity assessments. The results in this study also point
to the importance of investigating the environmental performance of a product based on fossil or renewable feedstock from
a life cycle perspective.
Recommendations and Perspectives The results in this study show that an efficient way to improve the wood coating industry environmentally is to increase the
utilization of UV lacquers that are 100% UV-based. These coatings can also be even further improved by introducing biocatalytic
processes and producing epoxides and diacrylates from renewable raw material instead of the fossil-based ones produced with
conventional chemical methods in use today. In doing this, however, choosing a vegetable oil with good environmental performance
is important. An alternative application of the ‘green wax’ analysed in this study may be as an ingredient in health care
products, for example, which may result in greater environmental benefits than when the wax is used inwood coating products.
The results in this study illustrate the importance of investigating the environmental performance of a product from cradle-to-grave
perspective and not consider it ‘green’ because it is based on renewable resources. 相似文献
355.
The aim of this project is to investigate the method of using a common buffer to determine the degree of stabilization and secretion of two drug molecules that have been analyzed in vitro. First, magnetic nanoparticles were synthesized and their structure was identified by instruments such as XPS (X-ray photoelectron spectroscopy) and FT-IR (Fourier transform infrared spectroscopy). The main purpose of this study was to investigate the stabilization and release of methotrexate on the surface of magnetic nanoparticles. The two temperatures were 37 and 25°, respectively. After reaction with the biomolecules, the adsorption rate for both drug molecules was about 60–80. PBS buffer was also used for diffusion of biomolecules and the results were analyzed by spectrophotometer analysis. With these results, the adsorption of cysteine and MTX was more than 60% and its release rate in MNPS-IHSPN was up to 90%, which means that high-strength stabilization and release by magnetic nanoparticles under external magnetic field and in vitro confirmed. The result of this project for the exchange of drugs by the surface of magnetic nanoparticles to repair damaged cells in the body of living organisms can be generalized. 相似文献
356.
Characterisation of cellular adhesion reinforcement by multiple bond force spectroscopy in alveolar epithelial cells 下载免费PDF全文