The gas chromatographic separation of fatty acid methyl esters (FAMEs) on ionic liquid stationary phases was investigated. Seven commercially available ionic liquid columns were tested using a test mixture containing 37 fatty acid methyl esters. The influence of column temperature on the elution order was studied using five different temperature programs. Retention times were highly reproducible. Similar retention behavior was observed for the IL59, IL60, and IL61 columns. The peak pair C18:1 cis/trans was not baseline resolved on these columns, whose stationary phases are highly similar. C18:2 cis/trans, C18:3 n6/n3, and C20:3 n6/n3 were baseline separated on all columns. Baseline separation of the complete test mix was only obtained on the IL82 column using a heating rate of 5 K/min. In general, retention times decreased with increasing column polarity but unsaturated FAMEs were retained stronger compared to their saturated counterparts. Except for the IL59 column, retention crossover was observed when the temperature program was changed. 相似文献
The unique mechanical performance of nacre, the pearly internal layer of shells, is highly dependent on its complex morphology. Inspired by the structure of nacre, the fabrication of well‐ordered layered inorganic–organic nanohybrids is presented herein. This biomimetic approach includes the use of a block copolymer template, consisting of hydrophobic poly(vinylidene fluoride) (PVDF) lamellae covered with hydrophilic poly(methacrylic acid) (PMAA), to direct silica (SiO2) mineralization. The resulting PVDF/PMAA/SiO2 nanohybrid material resembles biogenic nacre with respect to its well‐ordered and layered nanostructure, alternating organic–inorganic phases, macromolecular template, and mild processing conditions.
Endocytosis is a fundamental process involved in trafficking of various extracellular and transmembrane molecules from the cell surface to its interior. This enables cells to communicate and respond to external environments, maintain cellular homeostasis, and transduce signals. G protein-coupled receptors (GPCRs) constitute a family of receptors with seven transmembrane alpha-helical domains (7TM receptors) expressed at the cell surface, where they regulate physiological and pathological cellular processes. Several herpesviruses encode receptors (vGPCRs) which benefits the virus by avoiding host immune surveillance, supporting viral dissemination, and thereby establishing widespread and lifelong infection, processes where receptor signaling and/or endocytosis seem central. vGPCRs are rising as potential drug targets as exemplified by the cytomegalovirus-encoded receptor US28, where its constitutive internalization has been exploited for selective drug delivery in virus infected cells. Therefore, studying GPCR trafficking is of great importance. This review provides an overview of the current knowledge of endocytic and cell localization properties of vGPCRs and methodological approaches used for studying receptor internalization. Using such novel approaches, we show constitutive internalization of the BILF1 receptor from human and porcine γ-1 herpesviruses and present motifs from the eukaryotic linear motif (ELM) resources with importance for vGPCR endocytosis. 相似文献
Chagas disease (CD) can be accurately diagnosed by detecting Trypanosoma cruzi in patients’ blood using polymerase chain reaction (PCR). However, parasite-derived biomarkers are of great interest for the serological diagnosis and early evaluation of chemotherapeutic efficacy when PCR may fail, owing to a blood parasite load below the method’s limit of detection. Previously, we focused on the detection of specific anti-α-galactopyranosyl (α-Gal) antibodies in chronic CD (CCD) patients elicited by α-Gal glycotopes copiously expressed on insect-derived and mammal-dwelling infective parasite stages. Nevertheless, these stages also abundantly express cell surface glycosylphosphatidylinositol (GPI)-anchored glycoproteins and glycoinositolphospholipids (GIPLs) bearing nonreducing terminal β-galactofuranosyl (β-Galf) residues, which are equally foreign to humans and, therefore, highly immunogenic. Here we report that CCD patients’ sera react specifically with synthetic β-Galf-containing glycans. We took a reversed immunoglycomics approach that entailed: (a) Synthesis of T. cruzi GIPL-derived Galfβ1,3Manpα-(CH2)3SH (glycan G29SH) and Galfβ1,3Manpα1,2-[Galfβ1,3]Manpα-(CH2)3SH (glycan G32SH); and (b) preparation of neoglycoproteins NGP29b and NGP32b, and their evaluation in a chemiluminescent immunoassay. Receiver-operating characteristic analysis revealed that NGP32b can distinguish CCD sera from sera of healthy individuals with 85.3% sensitivity and 100% specificity. This suggests that Galfβ1,3Manpα1,2-[Galfβ1,3]Manpα is an immunodominant glycotope and that NGP32b could potentially be used as a novel CCD biomarker. 相似文献
Fungal infections of cultivated food crops result in extensive losses of crops at the global level, while resistance to antifungal agents continues to grow. Supercritical fluid extraction using CO2 (SFE-CO2) has gained attention as an environmentally well-accepted extraction method, as CO2 is a non-toxic, inert and available solvent, and the extracts obtained are, chemically, of greater or different complexities compared to those of conventional extracts. The SFE-CO2 extracts of Achillea millefolium, Calendula officinalis, Chamomilla recutita, Helichrysum arenarium, Humulus lupulus, Taraxacum officinale, Juniperus communis, Hypericum perforatum, Nepeta cataria, Crataegus sp. and Sambucus nigra were studied in terms of their compositions and antifungal activities against the wheat- and buckwheat-borne fungi Alternaria alternata, Epicoccum nigrum, Botrytis cinerea, Fusarium oxysporum and Fusarium poae. The C. recutita and H. arenarium extracts were the most efficacious, and these inhibited the growth of most of the fungi by 80% to 100%. Among the fungal species, B. cinerea was the most susceptible to the treatments with the SFE-CO2 extracts, while Fusarium spp. were the least. This study shows that some of these SFE-CO2 extracts have promising potential for use as antifungal agents for selected crop-borne fungi. 相似文献
The precursors with a low manganese content ≤ 0.07% Mn were synthesized by spontaneous crystallization from Zn2+, Mn2+ and C2O42−-containing solutions. The initial ratio Zn2+:C2O42− = 1:1 and 1:2 influences the morphology and prevailing orientations of the crystallites in the oxalate samples. The presence
of such small Mn content in the samples does not change the morphology or size of the crystals. The ZnO and Mn/ZnO oxides
with manganese content from 0.51×10−2 to 15.1×10−2 Wt % are obtained after thermal decomposition of the oxalates. The oxides preserved the morphology of the precursors. The
catalytic tests show that the pure ZnO has a poor activity for CO oxidation reaction. Its doping with Mn promotes the catalytic
activity (up from twice to five times) in spite of the very low contents of the dopants. The observed increase of the activity
depends on both dopant concentration and Zn2+:C2O42− ratio, probably due to the different mechanism of the manganese inclusion and different morphology of the oxides. The catalysts
of the 1:2 series are more active in CO oxidation reaction.
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The spray roasting process is recently applied for production of catalysts and single metal oxides. In our study, it was adapted for large-scale manufacturing of a more complex mixed oxide system, in particular symmetric lithium nickel manganese cobalt oxide (LiNi1/3Co1/3Mn1/3O2—NMC), which is already used as cathode material in lithium-ion batteries. An additional lithiation step was coupled with the main process in order to obtain the desired layered structure. Thermogravimetric analysis and high-temperature X-ray diffractometry built the basis for determining suitable synthesis temperature regions for the used chloride precursors and the post-treatment step. The optimized process was proven on an industrial pilot line where a setup for minimum production capacity of 12 kg h?1 was possible. The powder obtained directly after roasting had a very striking morphology compared to the final lithiated product. Hollow aggregates (≥250 μm) with overall 10.926 m2 g?1 surface area and a pore diameter of 3.396 nm were observed. Their well-faceted primary particles were converted into nanosized spheres after lithiation, building a few micrometer big high-porous agglomerates. Actual composition was verified by inductively coupled plasma atomic emission spectroscopy analysis, and the crystal structure and corresponding unit cell parameters were identified and confirmed by Rietveld fit of the derived X-ray diffraction pattern. The initial electrochemical measurements show a 149-mAh g?1discharge capacity, as determined from cyclic voltammetry. 相似文献
This paper describes a qualitative study that examines in more detail the question of how teachers’ beliefs may influence the intention to implement change as suggested by a professional development initiative. Several teachers in Germany took part in a professional development initiative for modelling. The course comprised five workshops spread over 2008. A part of our evaluation of the course involved interviewing six teachers after they had taken part. Teachers were interviewed about the impact the course had had on them, the opportunities and any related impediments they saw for modelling, and the way in which they typically taught. The interviews were evaluated using codes. Although the sample is very small, the cases allow for interesting insights, and for the hypotheses that teachers’ beliefs about effective teaching seem to have a major impact on whether or not they intend to change their classroom practice, as suggested by the professional development initiative, and on whether or not teachers perceive the context in which they are teaching (school head, parents, students, etc.) as supportive. 相似文献