Synthesis and Cytotoxic Activity of 4-Substituted 3-Cyano-6,6-dimethyl-5,6-dihydro-2-pyranones

The respective 4-(arylvinyl)lactones and compounds of the Michael adduct type were synthesized by the condensation of substituted benzaldehydes with 3-cyano-4,6,6-trimethyl-5,6-dihydro-2-pyranone in the presence of catalytic amounts of sodium hydroxide. It was shown by the semiempirical AM1 method that the indicated products can be formed through one and the same intermediate compound. Some of the synthesized phenylvinyl-5,6-dihydro-2-pyranones have a cytotoxic effect, and this corresponds to the prognosis of the OREX expert system.     

Solid-phase synthesis of N-labeled acylpentamines as reference compounds for the MS/MS investigation of spider toxins

A solid-phase route for synthesis of ¹⁵N-labeled acylpolyamines is described. Utilizing alkylation at benzylic N-atom as a key step, ¹⁵N-atoms are incorporated by stepwise construction of the polyamine framework on the solid support. The derivatives were used as reference compounds for the investigation of the MS/MS behavior of spider toxins.     

反应条件对Mo2C/Al2O3催化的POM制合成气的影响

考察了反应温度、气体空速和进料中CH4：O2比值对Mo2C／Al2O3催化的POM反应制合成气的影响．结果发现较高的温度具有较高的甲烷转化率、CO和H2的选择性；而在较低的温度下，对CO的选择性比对H2的影响更大．反应气体的空速较小时对于甲烷的转化率、CO和H2的选择性是有利的；而在较高的气体空速下，氢气的选择性则更低．进料中CH4：O2比值稍高于2：1时有利于获得高的甲烷转化率、CO和H2的选择性．并且还可以增加催化剂的稳定性．当CH4：O2比值低于2：1时．甲烷转化率、CO和H2选择性随反应的进行急剧下降．而当此比值调整到高于2：1时．转化率和选择件都可以得到恢复。     

Investigations for Modification of Polyacrylamide-Bentonite by Phytic Acid and its Usability in Fe3+, Zn2+ and UO2 2+ Adsorption

Composite of polyacrylamide-bentonite (PAA-B) was prepared by direct polymerisation of PAA in a suspension of bentonite (B). Adsorption and thermodynamic features of phytic acid (Phy) adsorption onto B, PAA and PAA-B, and those of Fe³⁺, Zn²⁺, UO₂ ²⁺ adsorption onto PAA-B and its modification by Phy (PAA-B-Phy) have been investigated. The reusability, storagability, ion selectivity and recoverability of sorbed ions with 1 M HCl have also been considered.The chemical and physical structure of adsorbents has been characterised by means of FT-IR and XRD. All adsorption isotherms for Phy and the ions were L-type of the Giles classification except, the one which is S type for adsorption of Phy onto PAA. The maximum adsorption capacities for the ions adsorbed were in order of UO₂ ²⁺ > Fe³⁺ > Zn²⁺ for PAA-B and Zn²⁺ > Fe³⁺ > UO₂ ²⁺ for PAA-B-Phy. Langmuir equilibrium constants for the adsorption of ions onto PAA-B-Phy were significantly higher than those found for PAA-B; the magnitude of increase for UO₂ ²⁺ was about 100. The thermodynamic parameters indicated that adsorption reactions are spontaneous in terms of adsorption free enthalpy.The chemical structure of PAA-B-Phy was not changed at the end of the studies of reusability and storagability. The composite was selective for UO₂ ²⁺ of the ions of interest.The composite of PAA-B and its modification by Phy have been used for the first time in this investigation. It is proposed that the composites can be practically used in the investigations and applications of adsorption.     

Chemical maps of patterned samples by microline‐imaging laser‐induced plasma spectrometry

The potential of a microline‐imaging laser‐induced plasma spectrometry (LIPS) system for surface and depth analysis of heterogeneous solid samples in air at atmospheric pressure has been demonstrated. A pulsed Nd : YAG laser beam operating at 532 nm, with a homogeneous energy distribution (flat top laser), was used to generate a microline plasma on the sample surface. Subsequent light from the microline plasma was resolved spectrally and spatially and detected with an imaging spectrograph and an intensified charged‐coupled device detector. A patterned metal sample was chosen as the most appropriate for this study. Three‐dimensional chemical maps of Ni and Cu from the edge connectors of a printed circuit board have been obtained. With this experimental configuration, the lateral resolution (limited by crater width) was 42 µm and the spatial resolution along the spectrometer slit was 17.4 µm. The results illustrate the capability of microline imaging for fast mapping of large‐area samples and for depth profiling purposes. Copyright © 2003 John Wiley & Sons, Ltd.     

Relative Abundance of Alpha-Amylase/Trypsin Inhibitors in Selected Sorghum Cultivars

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, {"type":"entrez-protein","attrs":{"text":"P81367","term_id":"3913899","term_text":"P81367"}}P81367 and {"type":"entrez-protein","attrs":{"text":"P81368","term_id":"3913900","term_text":"P81368"}}P81368; both reviewed and a targeted LC–MS/MS method was developed to analyze these. Quantifier peptides ELAAVPSR ({"type":"entrez-protein","attrs":{"text":"P81367","term_id":"3913899","term_text":"P81367"}}P81367) and TYMVR ({"type":"entrez-protein","attrs":{"text":"P81368","term_id":"3913900","term_text":"P81368"}}P81368) 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.     

Novel visible-light-driven photocatalyst of NiO/Cd/g-C3N4 for enhanced degradation of methylene blue

Novel NiO/Cd/g-C₃N₄ photocatalysts were synthesized using a green and straightforward microwave-assisted method and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), the Brunauer–Emmett–Teller (BET) method, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and ultraviolet–visible spectroscopy (UV–Vis). The ternary NiO/Cd/g-C₃N₄ nanocomposites were evaluated for the degradation of methylene blue (MB) at room temperature under the visible light irradiation. Experimental results revealed that the weight percent of cadmium had a remarkable effect on the photodegradation efficiency. The NiO/Cd/g-C₃N₄ (0.1%) sample exhibited superior activity in the degradation reaction. The activity of this nanocomposite was about 4.5 and 3.25 fold higher than those of the pure g-C₃N₄ and NiO/g-C₃N₄ samples in the degradation of MB, respectively. The enhanced photocatalytic activity was attributed to the low energy gap, increased absorption capacity of the visible light, and efficient suppression of the recombination of photogenerated electron-hole pairs. A detailed photocatalytic mechanism over the nanocomposite of NiO/Cd/g-C₃N₄ (0.1%) was proposed with superoxide radical anion O₂^– as the main reactive species. The stability of the nanocomposite was confirmed after four consecutive runs as well.     

活性炭复合滤嘴吸附性能的热脱附研究

采用热脱附与气相色谱-质谱联用技术对活性炭滤嘴中活性炭和乙酸纤维脱附的组分进行了定性分析,并用峰面积归一化法测定了所含挥发性成分的质量分数,活性炭脱附组分共鉴定出芳香族化合物、醛酮类、烟碱、酸类、酯类等62种挥发性化合物.结果表明方法具有较好的重现性;为评价活性炭滤嘴的吸附性能提供了一种参考方法.     

液质联用检测人体血浆中的阿奇霉素

采用高效液相色谱串联质谱技术(HPLC-MS/MS)测定人体血浆中阿奇霉素的浓度. 选用Lichrospher CN 柱, 流动相为V(乙腈)∶V(水)=40∶60(水中含体积分数为0.1%的甲酸和质量分数为0.1%的醋酸铵), 电喷雾离子源正离子方式检测. 该方法在2.34~600 ng/mL范围内线性关系良好, 定量下限为2.34 ng/mL(S/N>10), 回收率94.13%~97.42%, 基质效应92.50%~107.87%, 日内和日间测定药物浓度的相对标准偏差(RSD)均小于10.0%. 用该方法测定了24名男性健康志愿者单剂量口服500 mg阿奇霉素试剂和参比制剂于192 h内的血药浓度, 并进行了生物等效性研究.     

Advanced kinetic tools for the evaluation of decomposition reactions

Summary An advanced kinetic study on the thermal behaviour of pyrotechnic ignition mixtures has been carried out by differential scanning calorimetry using different B/KNO3 mixtures (50:50, 30:70, 20:80) as a model reaction. The experimental conditions applied (isochoric conditions/closed crucibles and isobaric conditions/open crucibles) as well as the composition of the mixtures noticeably influences the relative thermal stabilities of the energetic materials. The kinetic study focused on the prediction of the thermal stability of the different mixtures both in extended temperature ranges and under temperature conditions at which ordinary investigation would be very difficult. Using advanced numerical tools [1], thermal ageing and influence of the complex thermal environment on the heat accumulation conditions were computed. This can be done for any surrounding temperature profile such as isothermal, non-isothermal, stepwise, modulated, shock, adiabatic conditions and additionally for temperature profiles reflecting real atmospheric temperature changes (yearly temperature profiles of different climates with daily minimal and maximal fluctuations). Applications of accurate decomposition kinetics enabled the determination of the time to maximum rate under adiabatic conditions (TMR_ad) with a precision given by the confidence interval of the predictions. This analysis can then be applied for the examination of the effects of the surrounding temperature for safe storage or transportation conditions (e.g. determination of the safe transport or storage temperatures).