Changes in Phenols,Polysaccharides and Volatile Profiles of Noni (Morinda citrifolia L.) Juice during Fermentation

The change in phenols, polysaccharides and volatile profiles of noni juice from laboratory- and factory-scale fermentation was analyzed during a 63-day fermentation process. The phenol and polysaccharide contents and aroma characteristics clearly changed according to fermentation scale and time conditions. The flavonoid content in noni juice gradually increased with fermentation. Seventy-three volatile compounds were identified by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS). Methyl hexanoate, 3-methyl-3-buten-1-ol, octanoic acid, hexanoic acid and 2-heptanone were found to be the main aroma components of fresh and fermented noni juice. A decrease in octanoic acid and hexanoic acid contents resulted in the less pungent aroma in noni juice from factory-scale fermentation. The results of principal component analysis of the electronic nose suggested that the difference in nitrogen oxide, alkanes, alcohols, and aromatic and sulfur compounds, contributed to the discrimination of noni juice from different fermentation times and scales.     

Volatile organic compounds in head and neck squamous cell carcinoma—An in vitro pilot study

Owing to the lack of specific symptoms, diagnosis of head and neck squamous cell carcinoma (HNSCC) may be delayed. We evaluated volatile organic compounds in tumor samples from patients suffering from HNSCC and tested the hypothesis that there is a characteristic altered composition in the headspace of HNSCC compared with control samples from the same patient with normal squamous epithelium. These results provide the basis for future noninvasive breath analysis in HNSCC. Headspace air of suspected tumor and contralateral control samples in 20 patients were analyzed using ion-mobility spectrometry. Squamous cell carcinoma was diagnosed in 16 patients. In total, we observed 93 different signals in headspace measurements. Squamous cell carcinomas revealed significantly higher levels of volatile cyclohexanol (0.54 ppb_v, 25th to 75th percentiles 0.35–0.86) compared with healthy squamous epithelium (0.24 ppb_v, 25th to 75th percentiles 0.12–0.3; p < 0.001). In conclusion, head and neck squamous cell carcinoma emitted significantly higher levels of volatile cyclohexanol in headspace compared with normal squamous epithelium. These findings form the basis for future breath analysis for diagnosis, therapy control and the follow-up of HNSSC to improve therapy and aftercare.     

Facile decolorization of methylene blue by morphology-dependence δ-MnO2 nanosheets -modified diatomite

In this work, coscinodiscus-diatomite and melosira-diatomite have been decorated by ultrathin birnessite MnO₂ (δ-MnO₂) nanosheets through a one-pot hydrothermal method without using any surfactants. The δ-MnO₂ nanosheets are observed to grow vertically on the purified melosira-diatomite as well as coscinodiscus-diatomite. Moreover, the two composites exhibit high efficiency for decomposing methylene blue (MB) in the presence of H₂O₂. The coscinodiscus-diatmite@MnO₂ achieves a removal rate of 81.8% (2 h), and yet melosira-diatomite@MnO₂ reaches a higher degradation rate of 91.3% in 2 h. Additionally, the effects of catalyst amount, catalysis reaction temperature, preparing time have also been investigated. In principle, the diverse diatomite@MnO₂ nanostructures not only present an environmentally friendly and low cost with a good cycling stability, but also offer a simple way for the catalytic degradation of dye waste water in practical applications.     

金催化剂上脂肪族硝基化合物与醛在氢气中选择还原耦合

采用TiO2上高度分散的金纳米粒子做催化剂，从脂肪族硝基化合物、醛和氢气可高选择性合成硝酮。与碳负载Pt催化剂相比，该催化体系上硝酮的选择性从50%增加到90%。其催化性能可有活性位结构、载体特性和反应条件精确调节。     

“On water” cascade synthesis of benzopyranopyrazoles and their macrocycles

Reported herein is an intramolecular 1,3-dipolar cycloaddition strategy for rapid entry into benzopyranopyrazoles (BPP) on water medium as “open flask chemistry” approach. The in situ generation of diazo functionality in two-step sequence from the appropriate alkylated salicylaldehydes undergoes smooth [3?+?2]-cycloaddition with unactivated alkynes/alkenes furnishing benzopyranopyrazoles in good yield. This methodology was also extended for the synthesis of pyrazole incorporated macrocycles. This cascade protocol involving water medium provides an atom-economical and environment friendly approach.     

Convenient and Efficient Preparation of Ethyl 6-n-Decyloxy-7-ethoxy-4-hydroxyquinoline-3-carboxylate

Ethyl 6-N-decyloxy-7-ethoxy-4-hydroxyquinoline-3-carboxylate has been synthesized from pyrocatechol in six steps and in 39.3% overall yield.     

Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC‐MS/MS assay for pharmacokinetic study

Six esterase inhibitors, namely EDTA·2Na⁺, NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis‐nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mm ) and BNPP (5 mm ), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q‐Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter‐ and intra‐run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions. Copyright © 2012 John Wiley & Sons, Ltd.     

Microwave-Assisted Chemoselective Regeneration of Carbonyl Compounds from Oximes by Silica Chromate/WET SiO2 Under Solvent-Free Conditions

The regeneration of carbonyl compounds from oximes were performed by using silica chromate and wet SiO ₂ (w/w 50%) under microwave irradiation and solvent-free conditions with excellent yields.     

膨胀石墨 3 mm波消光数值计算

为探讨膨胀石墨作为3 mm波干扰材料的消光、散射特性及其影响因素, 基于有限长度、有限电导率圆柱状导体的电磁散射, 利用矩量法建立了膨胀石墨的消光、散射、吸收及后向散射截面(雷达散射截面RCS)的计算式. 运用Mathematica编程计算并分析了膨胀石墨长度、半径、电导率、磁导率等因素与膨胀石墨消光、散射、吸收截面及RCS的关系. 结果表明: 当膨胀石墨的长度为1.5 mm、半径为0.05 mm时, 具有较好的消光、散射效果; 适当增大膨胀石墨的电导率、磁导率, 有利于提高其消光、散射能力. 本研究为探索增强膨胀石墨干扰3 mm波效果的技术途径提供了有价值的参考. 关键词： 膨胀石墨 石墨层间化合物 消光截面 矩量法