Controlled accommodation of metal nanostructures within the matrices of polymer architectures through solution-based synthetic strategies

Controlled accommodation of metal nanostructures (MNSs) into the matrix of a well-defined polymer architecture offers an effective approach to achieve hierarchically structured nanocomposites with tunable synergistic properties to broaden application potentials in the emerging fields of energy, environmental science, and medicine. This review focuses on the recently developed zero-dimensional and one-dimensional MNSs@polymer hybrid nanostructures obtained by solution-based synthetic strategies. Progress in the controlled synthesis of those hybrid nanostructures in terms of the number (e.g., monomer, dimer and trimer), organization manner (e.g., linear alignment or confined assembly in certain domains), and spatial arrangement (e.g., in the core and shell) of the MNSs within the distinct polymer matrices are detailed. The synergistic properties and potential applications of those MNSs@polymer hybrids associated with their compositions and morphologies are also reviewed.     

2-氯丙烯基异硫氰酸酯的重排反应机理探究

基于在合成2-氯丙烯基异硫氰酸酯过程中的气相色谱检测数据,提出了该重排反应的机理,并以热力学公式计算出了该反应的标准吉布斯自由能,提出了如何获取更高2-氯丙烯基异硫氰酸酯收率的实验优化方向;以实验验证了提出的重排反应机理,提出了气相色谱在跟踪反应进程时的最优化方法。     

Effects of fertilisation on the allyl isothiocyanate profile of above‐ground tissues of New Zealand‐grown wasabi

Wasabi (Wasabia japonica (Miq) Matsum) is a developing crop in New Zealand and is valued for its spicy taste and pungent smell. It is popular as a condiment for traditional and modern Japanese foods. However, the limited area suitable for wasabi production in Japan has resulted in inability to meet increasing market demand. Isothiocyanates (ITCs) are sulphur compounds responsible for the unique flavour of wasabi, with allyl isothiocyanate (AITC) being the main compound responsible for the pungency. In this study, AITC tissue concentration and yield were measured in three above‐ground tissues of the wasabi plant to investigate the effects of different fertiliser, manure and lime treatments. The highest tissue concentration of AITC was found in the rhizomes, ranging from 1564 to 3366 mg kg^?1 (fresh weight basis), while the petioles and leaves contained 254–373 and 453–643 mg kg^?1 respectively. Fertilisation with ammonium sulphate produced the highest‐quality rhizomes (72% increase in AITC yield) and petioles (64% increase), but the best response in the leaves (51%) resulted from the manure treatment. Nitrogen fertiliser alone reduced the AITC yield by up to 15%. These results should help in formulating guidelines for production of high‐quality wasabi tops containing high levels of AITC. © 2002 Society of Chemical Industry     

山葵酱的研制及营养成分分析

为了进一步开发利用山葵,采用机械打浆,把山葵根茎清洗消毒后,磨成浆,装瓶杀菌成为山葵酱。同时,用化学方法和仪器法分别进行营养成分的分析。结果表明,山葵酱口感好,呈绿色,有辛辣味,营养丰富,蛋白质含量5．65％,含有17种氨基酸,脂肪含量1．2％,维生素C含量169．2mg／100g,异硫氰酸酯含量0．80mol／mL,这是山葵酱含有的其他酱类食品不能相比的特有成分,有抗癌作用,是一种真正的绿色调味食品。这为进一步开发利用山葵植物提供了科学依据。     

Rat intestinal microbiota digest desulfosinigrin to form allyl cyanide and 1-cyano-2,3-epithiopropane

The ability of rat intestinal microbiota to digest sinigrin and desulfosinigrin was studied using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). When sinigrin was incubated with rat intestinal microbiota, up to 64% of the initial amount of sinigrin was degraded during 12 h, yielding allyl isothiocyanate (AITC) as the major product along with a minor amount of allyl cyanide (ACN) and a trace amount of 1-cyano-2,3-epithiopropane (CETP), although the amount of ACN exceeded that of AITC after 12 h of incubation. In contrast, when desulfosinigrin was incubated with rat intestinal microbiota for 6 h, desulfosinigrin was digested up to 69% to form ACN and CETP as the major products instead of AITC. Whether the epithiospecifier protein (ESP) is involved in CETP formation in the rat intestinal microbiota-mediated degradation of desulfosinigrin remains to be established. However, only a trace amount of desulfosinigrin was detected during incubation of sinigrin with intestinal microbiota, although the intestinal microbiota had distinct sulfatase activity when p-nitrocatechol sulfate was used as the substrate. This observation suggested that the sulfatase of the rat intestinal microbiota has a very poor specificity toward sinigrin, which may be one reason for the formation of trace amounts of CETP during the intestinal microbiota-mediated digestion of sinigrin.     

Antimicrobial Properties of Sinigrin and its Hydrolysis Products

Sinigrin, a thioglucoside of Cruciferae plants, may be enzymatically hydrolyzed to yield up to four distinct aglycones when the plants are injured or mechanically disrupted. These aglycones, allyl isothiocyanate (AITC), allyl cyanide (AC), 1-cyano-2,3-epithiopropane (CETP), and allyl thiocyanate (ATC), were tested for their minimum inhibitory concentration (MIC) in broth to 9 species of bacteria and 8 species of yeasts. Sinigrin, AC, and CETP at 1,000 ppm were not inhibitory to any of the bacteria or yeasts tested. The inhibitory activity of ATC was uncertain due to its gradual conversion to AITC. AITC had an MIC of 50 to 1,000 ppm for bacteria and 1 to 4 ppm for nonxerotolerant yeasts, and, against xerotolerant yeasts at 50 ppm, it retarded but did not prevent growth.     

Antiyeast Activity of Heated Garlic in the Absence of Alliinase Enzyme Action

Garlic heated to 121 °C was found to strongly inhibit the growth of yeasts, but not that of bacteria. The potency and stability of the antiyeast activity of heated garlic were compared with those of fresh garlic, garlic oil, and allyl isothiocyanate. The inhibitory activity of heated garlic was stable, and the minimum inhibitory concentration did not change for up to 30 d at 37 °C. The antiyeast activity of heated garlic was not influenced by pH. Alliin heated in distilled water showed an antiyeast activity pattern similar to that of heated garlic, suggesting that the compound(s) thermally generated from alliin are the principal antiyeast compound(s) of heated garlic. The antiyeast activity was increased as time of heating increased up to 45 min at 121 °C, and the activity did not change when garlic was further heated for up to 120 min.     

气相色谱法测定菜粕异硫氰酸酯不确定度评定

对采用气相色谱内标法测定菜粕中的异硫氰酸酯含量的测量不确定度进行了评定。建立测量模型,分析确定菜粕中异硫氰酸酯含量的不确定度来源,并对测量过程中的不确定度分量进行逐层分析与合成,当菜粕的丙烯基异硫氰酸酯含量为99.2 mg/kg时,得到其合成标准不确定度和扩展不确定度分别为2.2、4.4 mg/kg。结果表明,校正因子测定引入的不确定度分量对合成标准不确定度的贡献最大,样品重复测定、回收试验和添加内标溶液带来的不确定度分量也不容忽视,试样称量对总不确定度的贡献最小,为采用该方法测定菜籽饼粕中异硫氰酸酯含量的质量控制提供了理论依据。     

三唑类化合物杀菌剂的发展现状与展望

介绍了三唑类化合物杀菌剂的发展情况、三唑类化合物杀菌剂的主要类型及三唑类化合物结构与杀菌活性的关系。论述了取代基团和立体异构对三唑类化合物杀菌剂生物活性的影响。     

Anti‐influenza virus activity of extract of Japanese wasabi leaves discarded in summer

BACKGROUND: Japanese wasabi (Wasabia japonica) is now habitually used as a spice in some kinds of Japanese foods, and its pungent taste and flavor are preferred. Generally, rhizomes and winter leaves are used as a spice and for processed foods such as pickled wasabi. Since the leaf area of summer leaves is far greater than that of winter leaves, they are not used for food, and are discarded. Thus, we need to develop an effective use for summer leaves. We investigated anti‐influenza virus activity in these summer leaves as a new function. RESULTS: Seventy percent ethanol extracts of leaves harvested in July exhibited a high replication inhibition rate (98% or higher) in the type A strain (AH1N1, A/shimane/48/2002), its subtype (AH3N2, A/shimane/122/2002), and type B strain (B/shimane/2/2002). The extracts of summer leaves exhibited the same anti‐influenza virus activity as winter leaves, and showed a stronger activity than stems, roots, and rhizomes. CONCLUSION: A potent anti‐influenza virus activity was discovered in summer leaves of Japanese wasabi. The ethanol extracts inhibited influenza virus replication regardless of the hemagglutinin antigen type. Therefore, such extracts are expected to be a promising source of a novel anti‐influenza virus agent. Copyright © 2008 Society of Chemical Industry