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51.
Ester-functionalised poly(1-vinylpyrrolidin-2-one) (PVP) oligomers obtained by radical polymerisation in methyl propionate, diethyl malonate and diethyl 2-methylmalonate were characterised by NMR spectroscopy, and MALDI-TOF mass spectrometry. The chain-transfer constants were determined as 5.54 x 10(-4), 1.22 x 10(-3) and 1.70 x 10(-2), respectively, by measuring the variation of the number-average molecular weight on conversion. These values were compared with those of methyl isobutyrate (1.65 x 10(-3)) and ethyl lactate (1.03 x 10(-2)), which had been previously determined. A clear dependence was found on the reactivity of the mobile hydrogen atoms alpha with the ester group. All of the macromolecules carried a single ester function. Therefore, the re-initiation step by the CTA-derived radicals overwhelmingly prevailed over initiation by the primary radicals.  相似文献   
52.
We report a facile synthesis of fused dihydrotriazolo[1,5-a]pyrazinones and triazolobenzodiazepines by an Ugi/alkyne-azide cycloaddition synthetic sequence. The coupling of the Ugi multi-component reaction with the intramolecular alkyne-azide cycloaddition provides access to highly functionalized heterocyclic ring systems in two steps from easily available starting materials in excellent overall yields.  相似文献   
53.
Abstract

Development of functional food through their enrichment with herbal extracts is gaining much attention from the food industry. The present study evaluates the benefits, such as the oxidative stability and quality retention, of the enrichment of cucumber (Cucumis sativus) with natural phenolic compounds through immersion into a variety of herbal infusions. After a preliminary experiment with gallic acid solutions, the beneficial effect of hypotonic solutions was observed and the optimal process conditions were defined. The second step of the study involved the immersion of cucumber in the herbal infusions for 2.5?h at 70?°C. The total phenolic content (TPC), antiradical and antioxidant activity of osmo-treated slices were determined to evaluate the extent of bioactive compounds’ impregnation. During the immersion, TPC, antioxidant and antiradical activity significantly increased irrespective of the type of the herbal infusion. The TPC varied greatly, ranging from 1.41 to 781.14?mg GAE/kg of cucumber. The highest total phenolics were found in cucumber treated with Origanum vulgare infusion, followed by Jasminum officinale and Mentha spicata infusions. The aforementioned osmo-treated slices were also highly appreciated by the sensory panel; therefore, for those best performing herbal infusions, the third phase of this work involved the study of quality degradation under subsequent storage of the osmo-treated slices vs. the untreated ones. The results regarding color, texture, and visual assessment demonstrated the superior quality retention of the osmo-treated samples that exhibited a shelf life extension ranging from two- to almost four-fold compared to the untreated tissue.  相似文献   
54.
Quantitative structure-activity relationship (QSAR) analysis is a main cornerstone of modern informatic disciplines. Predictive computational models, based on QSAR technology, of peptide-major histocompatibility complex (MHC) binding affinity have now become a vital component of modern day computational immunovaccinology. Historically, such approaches have been built around semi-qualitative, classification methods, but these are now giving way to quantitative regression methods. The additive method, an established immunoinformatics technique for the quantitative prediction of peptide-protein affinity, was used here to identify the sequence dependence of peptide binding specificity for three mouse class I MHC alleles: H2-D(b), H2-K(b) and H2-K(k). As we show, in terms of reliability the resulting models represent a significant advance on existing methods. They can be used for the accurate prediction of T-cell epitopes and are freely available online ( http://www.jenner.ac.uk/MHCPred).  相似文献   
55.
Nitrate ions were used as the oxidant in the cathode chamber of a microbial fuel cell (MFC) to generate electricity from organic compounds with simultaneous nitrate removal. The MFC using nitrate as oxidant could generate a voltage of 111 mV (1,000 Ω) with a plain carbon cathode. The maximum power density achieved was 7.2 mW m−2 with a 470 Ω resistor. Nitrate was reduced from an initial concentration of 49 to 25 mg (NO3−N) L−1 during 42-day operation. The daily removal rate was 0.57 mg (NO3–N) L−1 day−1 with a voltage generation of 96 mV. In the presence of Pt catalyst dispersed on cathode, the cell voltage was significantly increased up to 450 mV and the power density was 117.7 mW m−2, which was 16 times higher than the value without Pt catalyst. Significant nitrate removal was also observed with a daily removal rate of 2 mg (NO3–N) L−1 day−1, which was 3.5 times higher compared with the operation without catalyst. Nitrate was reduced to nitrite and ammonia in the liquid phase at a ratio of 0.6% and 51.8% of the total nitrate amount. These results suggest that nitrate can be successfully used as an oxidant for power generation without aeration and also nitrate removal from water in MFC. However, control of the process would be needed to reduce nitrate to only nitrogen gas, and avoid further reduction to ammonia.  相似文献   
56.
Multifractal (MF) approach was applied for the analysis of ultraviolet/visible (UV/VIS) spectra as an independent confirmation of the diagnostic efficacy of UV/VIS spectral analysis of intraperitoneal fluids, ascites, taken from patients with a known clinical diagnosis. Recently, it was reported that from UV/VIS spectra differentiation of malignant from benign ascites is possible. Here, it was shown that by using MF analysis of UV/VIS spectra, the objective classification of UV/VIS spectra is possible. The applicability of UV/VIS analysis and MF classification of spectra were evaluated on N=68 cases, of which M=64 and B=4 were clinically confirmed as malignant and benign, respectively. The overall diagnostic efficacy was 89.71% when using on-line analysis of UV/VIS spectra (61 out of 68 samples were positively recognized: 58 malignant and 3 benign), and even 95.59% by using off-line MF classsification (65 out of 68 samples were classified correctly: 63 malignant and 2 benign). It can be inferred that UV/VIS spectral analysis of ascites, combined with MF analysis, could be suggested as a successful and safe screening method in the evaluation of intraperitoneal fluids.  相似文献   
57.
A mechanochemical desymmetrization of symmetrical bis- and tris-alkynes by a controlled 1,3-dipolar cycloaddition reaction using nitrile oxide dipoles (NOs). This operationally simple protocol allows access to 3,5-isoxazole-alkyne adducts from easily prepared or commercially available symmetrical bis- and tris-alkynes in moderate to excellent yields. In addition, we have highlighted the synthetic utility of 3,5-isoxazole-alkyne by developing a route to access, for the first time, β-ketoenamine-alkyne derivatives, and unsymmetrical bis-3,5-isoxazoles.  相似文献   
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