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21.
Eva Eichler Clarence Stanley Rooney Haydn Windsor Richard Williams 《Journal of heterocyclic chemistry》1976,13(4):841-844
The syntheses of some 1,8-naphthyridines substituted in the 6-position with heterocyclic groups are described. A synthetic route to 6-amino-5,7-dimethyl-1,8-naphthyridin-2(1H)one is also presented. 相似文献
22.
Accumulation of five heavy metal ions by five species of wood-rotting basidiomycetes during a 9-day cultivation was studied. Contents of Cd, Cu, Pb, and Zn were measured using ICP-MS; the amount of mercury was determined directly in solid samples using the Advanced Mercury Analyser. A standard operation procedure for the sample preparation and determination of metal content was developed and validated. Presence of Cd, Cu, Hg, and Pb decreased the accumulation of zinc by the fungi. The basidiomycete Pycnoporus cinnabarinus exhibited the highest metal binding capacity of all fungi tested. 相似文献
23.
The reaction of 1-(hydrazidomethyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline 3 with aromatic aldehydes yield hydrazones 4a,b or pyrimido[6,1-a]isoquinolines 5a-c depending upon the proportions of the reagents. With ketones, 3 gives only hydrazones 4a-d and 7 , which can be transformed to pyrimidoisoquinolines 10a-e and 11 with aldehydes. The ring closures are stereospecific; the relative configurations were determined by DNOE measurements. 相似文献
24.
Fluorescent behavior of B-phycoerythrin in microemulsions of aerosol OT/water/isooctane 总被引:3,自引:0,他引:3
Bermejo R Tobaruela DJ Talavera EM Orte A Alvarez-Pez JM 《Journal of colloid and interface science》2003,263(2):616-624
Taking advantage of its unusual fluorescent properties, the incorporation of B-phycoerythrin (B-PE) in aerosol OT (AOT, sodium bis-(2-ethylhexyl) sulphosuccinate)/water/isooctane microemulsions was investigated by following their steady-state and time-resolved fluorescence as a function of the water-to-surfactant molar ratio, w(0). The fluorescent intensity at 575 nm increased continuously with increasing water content, saturating at a w(0) around 35 and staying practically constant at w(0)> or =40. The steady-state anisotropy showed an initial increase with increasing water content until w(0)=23 and then decreased strongly, staying practically constant when w(0)> or =40. The values of the fluorescent parameters, anisotropy and fluorescent intensity, were unchanged when the water content of the system increased in the range between w(0)=40 to 50. This implies the effective incorporation of B-PE in the microemulsion droplets with w(0)> or =40, as well as the equilibrium of the dispersion at these water/surfactant ratios, since higher water content does not affect the main surrounding microenvironment of the protein. The overall incorporation in the microemulsion droplets caused minor spectroscopic changes with respect to biliprotein in aqueous solution of 20 mM sodium phosphate buffer, pH 7.0, such as a blue absorption shift of 3 nm and an emission shift of 1.5 nm, as well as a slight increase in excitation anisotropy spectrum mainly caused by a decrease in protein mobility. Therefore, there are no important interactions between the chromophores and the AOT sulfonate head groups. Emission intensity decays followed complex kinetics in both aqueous and dispersion media. The stability with time and temperature of the biliprotein in the microemulsion was higher than in the aqueous solution. All the results can be explained in terms of B-PE inclusion in the water droplets of AOT microemulsions where the protein has similar configuration and conformation to that in aqueous solution but with the chromophores more protected. 相似文献
25.
A systematic investigation of optimal conditions for determining three of the most common phenoxyl-type N-methylcarbamate pesticides (carbaryl, carbofuran and propoxur) in fruit juices by HPLC with peroxyoxalate-chemiluminescence detection is described. The required pre-column hydrolysis of pesticides and derivatization of their hydrolytic metabolites with dansyl chloride was simultaneously carried out in a short time thanks to the micellar catalytic effect provided by cetyltrimethyl ammonium bromide micelles on the hydrolysis step. The liquid chromatographic separation of the dansylated phenols was performed on a reversed-phase C18 column with isocratic elution. The analytes were detected by using an integrated derivatization chemiluminescence detection unit based on the bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide system. Fruit juice samples containing 4.0-1500 microg/l pesticides were analysed with a precision of ca. 6.5%. After contamination of the fruit juice samples, average recovery > 93% at fortification levels of 10-100 microg/l was obtained. 相似文献
26.
Synthesis, IR Spectrum, and Crystal Structure of N,N'-Bis(trimethylsilyl)benzamidinium Tetrachloroferrate(III) The title compound [C6H5? C(NHSiMe3)2][FeCl4] is obtained by the reaction of FeCl3 with N,N,N'-tris(trimethylsilyl)benzamidine in the presence of tetrahydrofurane, forming yellow, moisture sensitive crystals. The compound is characterized by its IR spectrum as well as by an X-ray structure determination. Space group P21/n, Z = 8, 5974 independent observed reflexions, R = 0.066. The lattice dimensions are at ?70°C: a = 2110.7, b = 1109.5, c = 2120.4 pm; β = 111.17º. The compound forms ion pairs, in which the H atoms of the amidinium cation are coordinated with one chlorine ligand of the FeCl4? ion in a chelating manner. 相似文献
27.
Sorel Tchewonpi Sagu Eva Landgrber Michal Rackiewicz Gerd Huschek Harshadrai Rawel 《Molecules (Basel, Switzerland)》2020,25(24)
Sorghum is of growing interest and considered as a safe food for wheat related disorders. Besides the gluten, α-amylase/trypsin-inhibitors (ATIs) have been identified as probable candidates for these disorders. Several studies focused on wheat-ATIs although there is still a lack of data referring to the relative abundance of sorghum-ATIs. The objective of this work was therefore to contribute to the characterization of sorghum ATI profiles by targeted proteomics tools. Fifteen sorghum cultivars from different regions were investigated with raw proteins ranging from 7.9 to 17.0 g/100 g. Ammonium bicarbonate buffer in combination with urea was applied for protein extraction, with concentration from 0.588 ± 0.047 to 4.140 ± 0.066 mg/mL. Corresponding electrophoresis data showed different protein profiles. UniProtKB data base research reveals two sorghum ATIs, and P81367; both reviewed and a targeted LC–MS/MS method was developed to analyze these. Quantifier peptides ELAAVPSR ( P81368) and TYMVR ( P81367) were identified and retained as biomarkers for relative quantification. Different reducing and alkylating agents were assessed and combination of tris (2 carboxyethyl) phosphine/iodoacetamide gave the best response. Linearity was demonstrated for the quantifier peptides with standard recovery between 92.2 and 107.6%. Nine sorghum cultivars presented up to 60 times lower ATI contents as compared to wheat samples. This data suggests that sorghum can effectively be considered as a good alternative to wheat. P81368相似文献
28.
Eva Matousková Charles Stegall 《Proceedings of the American Mathematical Society》1996,124(4):1083-1090
A Banach space is not reflexive if and only if there exist a closed separable subspace of and a convex closed subset of with empty interior which contains translates of all compact sets in . If, moreover, is separable, then it is possible to put .
29.
Anhydrites(II)- CaSO4 were prepared from two waste gypsums (PRECHEZA Perov, FOSFA Potorná). The samples of anhydrites(II) with sulphate activators were tested on spillage, beginning and the end of setting time, bending and pressure strength. Both sodium and potassium sulphates accelerated setting of anhydrite, more impressively that prepared from Potorná gypsum. The addition of Na2SO4 influenced the strength of this anhydrite very favourably. On the contrary K2SO4 influenced favourably the strength of Perov anhydrite. Results confirm the necessity to evaluate properties of such materials with respect to their origin. 相似文献
30.
Trifluoromethoxy-substituted anilines undergo hydrogen/lithium permutation ("metalation") with optional site selectivity depending on the N-protective group employed. N-tert-Butoxycarbonyl-2- and -4-(trifluoromethoxy)aniline react with tert-butyllithium at the nitrogen-adjacent 6- and 2-position affording, after electrophilic trapping, products 1-6. In contrast, deprotonation of the para isomer occurs at the oxygen-neighboring 3-position, giving rise to the acid 12, when the amino group is carrying two trimethylsilyl groups. sec-Butyllithium attacks 3-trifluoromethoxy-N-mono(trimethylsilyl)aniline at the 2-position, but 3-trifluoromethoxy-N,N-bis(trimethylsilyl)aniline at the 4-position to provide respectively the acids 10 and 11 after carboxylation. The synthesis of two new benzodiazepines illustrates (19 and 22) the preparative potential of the aniline functionalization mediated by organometallic reagents. 相似文献