Visualizing biochemical activities in living cells through chemistry

The development of molecular probes to visualize cellular processes is an important challenge in chemical biology. One possibility to create such cellular indicators is based on the selective labeling of proteins with synthetic probes in living cells. Over the last years, our laboratory has developed different labeling approaches for monitoring protein activity and for localizing synthetic probes inside living cells. In this article, we review two of these labeling approaches, the SNAP-tag and CLIP-tag technologies, and their use for studying cellular processes.     

Deodorization optimization of Camelina sativa oil: Oxidative and sensory studies

Camelina sativa oil (CO) is characterized by a high content (up to 40 wt %) of essential α‐linolenic acid and characteristic odour and flavour. Deodorization of highly unsaturated oils requires great attention as the refining process involves thermal treatment which affects oil integrity. In the present study RSM and principal component analysis (PCA) were used to optimize bench‐scale deodorization of CO. Mathematical models were generated through multiple regressions with backward elimination, describing the effects of process parameters (temperature, steam flow, time) on oil quality indicators [peroxide value (PV), p‐anisidine value (p‐AV), γ‐tocopherol (γ‐T) and oxidative stability (OS)]. Additionally, sensory evaluation was performed. RSM analysis showed a significant effect of deodorization temperature and to a lesser extent, deodorization steam flow and time on removal of oxidative compounds, flavour and odour. PCA of chemical and sensory results showed that deodorization temperature affected the sensory properties in the samples. The best conditions for removing undesirable flavour and odour were achieved by using a deodorization temperature of 195–210°C.     

Sorption properties of wood impregnated with aqueous solution of boric acid and montan wax emulsion

Nonbiocidal techniques for wood protection have become more and more important in the last few years. One of the possible treatments to enhance wood durability is use of water repellents. In this research, the influence of one of the possible water repellents, the montan wax emulsion, on the moisturizing and the sorption characteristics of impregnated wood was investigated. To achieve a better protection against wood decay fungi, wood was impregnated with montan wax emulsion enriched with boric acid. The equilibrium moisture content (MC) was monitored during the adsorption and the desorption processes at five levels of relative air humidity (RH₁ = 20%, RH₂ = 33%, RH₃ = 65%, RH₄ = 88%, and RH₅ = 98%). Water repellence efficiency was monitored in the chamber with high RH (87%) and during dipping in the water. Impregnated samples were also exposed outdoors in a covered position for 5 months to determine MC changes according to changes in outdoor humidity and temperature. The results showed that the sorption properties of the impregnated wood are strongly related to retention of preservative solutions after impregnation and its composition. Montan wax reduced equilibrium MC of the impregnated wood up to 25% (relatively), whereas specimens impregnated with combination of montan wax and boric acid resulted in decreased MC in some cases and in increased MC in some cases. The Guggenheim–Andersen–deBoer model of sorption isotherms was fitted to experimental data to explain the sorption mechanisms. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

CO2 laser-assisted preparation of transparent Eu2Ti2O7 thin films

We present a laser-assisted preparation of transparent europium-titanate Eu₂Ti₂O₇ thin films with tailored structural and optical properties. We have evaluated the effects of the irradiation time on the structural and the optical properties of the films. This approach allows the preparation of nanocrystalline crack-free films and micro patterns. The amorphous thin films were prepared by a sol-gel method. The films were annealed by a CO₂ laser beam for various time intervals. The laser irradiation induced a crystallization process that resulted in the formation of Eu₂Ti₂O₇ nanocrystals. The nanocrystals regularly grew with increasing irradiation time reaching the size from 25?nm to 45?nm. A film of a thickness 480?nm exhibited an optical transmission of 91.9% that is close to the maximal theoretical limit. The film's refractive index at 632?nm was 2.26. A micrometric pattern was prepared by a direct laser writing followed by a wet chemical etching. Feasibility of the demonstrated approach, together with the high film's quality, and europium-titanate chemical resistivity open up many opportunities for advanced applications. The approach can be used for a preparation of protective coatings and integrated photonic devices such as planar optical waveguides and couplers.     

Elimination of boron and lithium coexisting in geothermal water by adsorption-membrane filtration hybrid process

Direct release of geothermal waters to the environment may cause some damages to some plants because they contain toxic species such as boron, arsenic, fluoride etc. along with valuable minerals including lithium. In this study, a hybrid process combining adsorption and membrane filtration was used to separate boron and lithium simultaneously from geothermal water. According to the results obtained, separation efficiencies for lithium and boron from geothermal water were 100% and 83% using boron selective ion exchange resin Dowex XUS-43594.00 and lithium selective λ-MnO₂ adsorbent, respectively. The kinetic data of lithium and boron adsorption have been evaluated using pseudo-first order and pseudo-second-order kinetic models.     

Dynamic colorimetric properties of mixed thermochromic printing inks

Leuco dye‐based thermochromic inks reversibly change from the coloured to the discoloured state in a defined, comparatively wide temperature region. Inside this region, the colour of a sample depends on the temperature and thermal history, which is known as the hysteresis effect. The colour of such a sample as a function of temperature has the shape of a hysteresis loop. Commercially available thermochromic inks have different loops, narrow or broad, and their shapes range from approximately symmetric to highly asymmetric. These properties are also important in mixtures of inks. The hysteresis loop of a mixture reveals its binary nature if the individual pure inks have well‐separated hysteresis. When inks with close‐separated loops, i.e. with similar activation temperatures, are mixed together, the loop of the mixture fuses together into an apparently single loop. Our research shows that some of their dynamic colour properties could be predicted in advance. However, optic and colorimetric properties of mixtures are not additive.     

中都河流域“8·16”山洪致灾机理分析

我国西南地区地形地貌条件复杂，极端暴雨山洪灾害频发，显著制约地区社会经济发展。为科学认识暴雨山洪形成过程，揭示受灾地区致灾机制，构建符合区域特征的山洪灾害预警体系，以四川省屏山县中都河流域“8.16”山洪灾害为例，结合实地调查及基础资料，从地区降雨特性、洪水陡涨过程及人类活动三方面入手，系统分析了此次暴雨山洪的灾变响应过程，以及采用水位流量反推法和洪水上涨率判定法计算山洪灾害预警指标阈值。结果表明：此次山洪灾害成因主要在于上游马边县地区短时强降雨导致下游屏山县中都镇河水陡涨，极大缩短了沿河居民转移时间；当地居民围滩造地侵占河道，减少了行洪面积，属于典型的地区强降雨与人类活动综合影响下的突发性暴雨山洪灾害；对比上述两种预警方法的结果，发现水位流量反推法预警精度稍差且多次出现漏警，洪水上涨率法预警期显著延长，预警效果更为可靠。因此，建议中都河流域山洪灾害防御采用洪水上涨率法和传统预警相结合，以流域划分模式构建马边屏山两县行政联合的山洪预警体系，可为该区域乃至其他类似山洪灾害频发地区的防治提供科学依据。     

Berechnung von dreidimensionalen elektromagnetischen Feldern bei der induktiven Erwärmung

Übersicht Es wird ein numerisches 3D-Berechnungsverfahren vorgestellt, mit dem die elektromagnetischen (EM-) Felder bei induktiver Hochfrequenz-(HF-) oder Banderwärmung, also im Fall dünner stromführender Schichten, simuliert werden. Darüber hinaus lassen sich Leistungs- und Kraftverteilungen sowie integrale Größen, wie z. B. Impedanz, Spannung und Wirkleistung, ermitteln. Für das Berechnungsprogramm werden die prozeßrelevanten Teile der betrachteten Anlagen entsprechend ihrer elektromagnetischen Eigenschaften bestimmten Gruppen zugeordnet. Für jede Gruppe gelten spezifische Randbedingungen an der Oberfläche bezüglich der EM-Felder. Das Berechnungsprogramm basiert auf der Boundary-Element-Methode (BEM) und berücksichtigt die anlagenspezifischen Symmetrien, so daß Rechner genutzt werden können, die in Forschung und Entwicklung heute allgemein zugänglich sind (PC, Workstation). Am Beispiel zweier Anwendungsfälle wird die Leistungsfähigkeit des entwickelten Programmpaketes aufgezeigt.

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Calculation of threedimensional electromagnetic fields during induction heating

Contents A numerical 3D-calculation method for the simulation of the electromagnetic field during high frequency induction heating or induction strip heating, i.e. in case of thin current-carrying layers, is presented. In addition, the described programme allows to calculate the distributions of power and force as well as integral quantities, for example the impedance, the voltage and the active power. The parts of the setup to be considered are assigned to certain groups according to their electromagnetic properties. Each group has its specific boundary conditions at the surface describing the electromagnetic field. The calculation program uses the boundary element method and takes into account the set-up specific symmetries. Therefore the program runs on computers (PC, Workstations), which are widely available for research and development purposes nowadays. Finally, two examples basing on industrial applications show the efficiency of the developed program.

     

Amphiphilic Properties of Dodecylammonium Chloride/4-(1-Pentylheptyl) Benzene Sodium Sulfonate Aqueous Mixtures and Study of the Catanionic Complex

Surfactants are often used in supramolecular chemistry, due to their ability to self-organize. Surfactant molecules aggregate spontaneously and reversibly to adopt a defined intermolecular arrangement. In this work, general phase behavior, adsorption and association in aqueous mixtures of dodecylammonium chloride, DACl and sodium 4-(1-pentylheptyl) benzenesulfonate, NaDBS, were studied by a combination of techniques including surface tension and conductivity measurements, light scattering and optical microscopy. The strong synergistic properties of the system were brought out with the Regular Solution Theory. Various colloidal objects are observed in wide range of composition: conventional small vesicles, large giant multilamellar or multivesicular vesicles. An excess of NaDBS provides extremely large tubular and elongated multilamellar vesicles. The new catanionic 1:1 complex, dodecylammonium-4-(1-pentylheptyl) benzenesulfonate, formed in the equimolar conditions is a result of intramolecular charge neutralization. The thermal properties of this solid compound were examined by thermal polarizing microscopy, differential scanning calorimetry, and X-ray diffraction. The most probable ion-pair amphiphilic cluster of the crystal smectic phase, at room temperature, consists of ionic groups formed in ordered layers with dodecyl chains packed into somewhat disordered layers, tilted to the layer plane.     

The Effect of Electroporation of a Lyotroic Liquid Crystal Genistein-Based Formulation in the Recovery of Murine Melanoma Lesions

A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen) was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema). Although hematoxylin–eosin (HE) staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE), or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ) antibody.