Chemical shift assignments of two oleanane triterpenes from Euonymus hederaceus

INTRODUCTION Euonymus hederaceus champ.ex Benth (Celas-traceae) has been used as a traditional medical plant (Chang et al., 1996). Two compounds, 12-oleanene-3,11-dione and 28-hydroxyolean-12-ene-3,11-dione (Fig.1) were isolated by its phytochemical investiga-tion. The complete 1H and 13C chemical shift as-signments of 12-oleanene-3,11-dione are described here for the first time with 1D and 2D NMR, cor-recting some data in Yuan et al.(1994). The 13C as-signments of 28-hydroxyolean-1…     

Isolation,chemical characterization,and immunomodulatory activity of naturally acetylated hemicelluloses from bamboo shavings

Bamboo shavings, the outer or intermediate layer of bamboo stems, are the bulk of by-products produced in bamboo processing. In this study we investigated the isolation, chemical characterization, and immunostimulatory activity in vitro of the hemicelluloses from bamboo shavings. Shavings were first pretreated by steam explosion. The optimal pretreatment was found to be steam explosion at 2.2 MPa for 1 min. Following this pretreatment, the yield of hemicelluloses reached (2.05±0.22)% (based on the dry dewaxed raw materials), which was 5.7-fold higher than that of untreated samples. Bamboo-shavings hemicellulose (BSH) was then prepared by hot water extraction and ethanol precipitation from the steam-exploded shavings. Purification of BSH by anion-exchange chromatography of diethylaminoethanol (DEAE)-sepharose Fast Flow resulted in a neutral fraction (BSH-1, purity of 95.3%, yield of 1.06%) and an acidic fraction (BSH-2, purity of 92.5%, yield of 0.79%). The weight-average molecular weights (M _w) of BSH-1 and BSH-2 were 12 800 and 11 300 g/mol, respectively. Chemical and structural analyses by Fourier transform infrared spectroscopy (FT-IR), 1D (¹H and ¹³C) and 2D (heteronuclear single quantum correlation (HSQC)) nuclear magnetic resonance (NMR) spectra revealed that BSH-1 was O-acetylated-arabinoxylan and BSH-2 was O-acetylated-(4-Omethylglucurono)- arabinoxylan. BSH-1 had a higher content of acetyl groups than BSH-2. For the immunomodulatory activity in vitro, BSH and BSH-2 significantly stimulated mouse splenocyte proliferation while BSH-1 had no effect; BSH, BSH-1, and BSH-2 markedly enhanced the phagocytosis activity and nitric oxide production of the murine macrophage RAW264.7 in a dose-dependent manner. Our results suggest that the water-extractable hemicelluloses from steam-exploded bamboo shavings are naturally acetylated and have immunostimulatory activity.     

Caffeic acid product from the highly copper-tolerant plant Elsholtzia splendens post-phytoremediation: its extraction, purification, and identification

In the current study, caffeic acid was an important metabolite in the highly copper-tolerant plant Elsholtzia splendens. Preparation and purification of caffeic acid were performed on the dried biomass of the plants by means of sonication/ethanol extraction, followed by purification using a macroporous resin (D101 type) column and silica gel chromatography. The faint-yellow caffeic acid product was yielded with a purity of 98.46%, and it was chemically identified from spectra of Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR)/carbon nuclear magnetic resonance (¹³C NMR), and electrospray ionization mass spectrometry (ESI-MS). Caffeic acid is a possible product from the post-harvest processing of Elsholtzia splendens biomass.     

Individual assignments and academic dishonesty — Exploring the learning Conundrum

A survey of university business professors¹ focused on their use of individual assignments in courses and their views on cheating and its impact on student learning. Based on responses from 456 professors (37% response rate) from Ontario, Canada. it was concluded that most facult² believe that individual assignments are effective learning tools and that cheating on these assignments is a serious offence. They believe that cheating occurs widely, but continue to use these assessments, with some alterations, to ensure that students obtain learning benefits. The survey findings varied across disciplines and tenure status. A framework is proposed to explain the faculty perspective and the outcomes that professors experience. The adjustments they make to individual assignments are influenced by multiple factors that are internal (university policies and regulations) and external (internet usage) to the university. The discussion centres on the three stakeholders — faculty, students and administration — the need for culture change, and the role of honor codes in controlling cheating and supporting a learning environment.     

“一锅煮”法合成7-氟喹唑啉-2,4-二酮

本研究发展了一种环境友好,操作简单的7-氟喹唑啉-2,4-二酮"一锅煮"合成方法。以2-氨基-4-氟苯甲酸为原料,常温下以水为溶剂,与异氰酸成脲,后在强碱条件下环合成相应的钠盐,最后酸化即得7-氟喹唑啉-2,4-二酮。该合成方法在室温水中进行,仅需简单的搅拌和过滤操作,即可得到高纯度的目标化合物,适合大量制备该化合物。     

Distribution of<Emphasis Type="Italic">H. pylori</Emphasis> antigens in gastric mucosa and its significance

Objective: To investigate the distribution ofH. pylori antigens in the gastric mucosa in patients withH. pylori infection, and the relationship between the distribution and gastric cancer. Methods: Of 112 patients confirmed by pathological study to have chronic superficial gastritis, precancerous changes (chronic atrophic gastritis, intestinal metaplasia or atypical hyperplasia) and gastric cancer, 28 wereH. pylori negative and 84 wereH. pylori positive.H. pylori antigens in the gastric mucosa were detected by immunohistochemistry. Results: TheH. pylori positive group, comprised 12 of 22 (50.0%) in the chronic superficial gastritis group, 22 of 25 (88.0%) in the precancerous changes group and 13 of 35 (37.1%) in the gastric cancer group. The positive rates ofH. pylori antigens in the cytoplasm progressively increased, respectively at 0.0% (0/12), 63.6% (14/22) and 84.6% (11/13) for the same groups (χ ²=19.76,P=0.000);H. pylori antigens were located in the mucus layer and above the neck of the mucosal gland in 9 of 12 (75.0%) cases with chronic superficial gastritis, at the neck of the mucosal gland and the isthmus in 12 of 22 (54.5%) cases with precancerous changes, below the isthmus in 9 of 13 (69.2%) cases with gastric cancer (χ ²=25.30,P=0.000). In theH. pylori negative group, noH. pylori antigen was observed. Conclusion: With the progression of chronic superficial gastritis→precancerous changes→gastric cancer,H. pylori antigens progressively migrated from the outer part to the inner part of the cell, and from the superficial to the deep gastric mucosa.     

Applications of water sensitivity in situ remediation at saltwater-freshwater interface

Based on the laboratory experiments with the saltwater and freshwater replacing each other in the level sand column, taking the kaolin, illite, smectite, bivalent hydrargyrum ion (Hg²⁺) and phenol (C₆H₅OH) as examples, this paper studies the applications of water sensitivity in situ remediation in saltwater-freshwater transition zone. In the water sensitivity process, the release and migration of clay minerals can make the hydraulic conductivity (HC) decrease and pollutants remove. A new type of low penetrable or impenetrable purdah can be built by adding clay minerals into the sand media to replace the underground concrete impenetrable wall to prevent seawater intrusion, and a number of the heavy metals and organic pollutants in the sand media can be removed by in situ remediation. The results show that the content of kaolin and illite influences the water sensitivity process slightly, and HC of the sand columns descends from 0.011 cm/s to 0.001 4 cm/s and 0.001 2 cm/s respectively even if the content reaches 12% (weight ratio, sic passim). However, for smectite, HC descends sharply to about 1×10⁻⁸ cm/s when its content reaches 4%, and no water can flow through the sand columns beyond 5%. The particle release and migration processes can remove the Hg²⁺ and C₆H₅OH out of the sand columns efficiently, the removing rate of Hg²⁺ is 31.68% when the freshwater and saltwater are filtered through the sand columns polluted by Hg²⁺, while it is 67.55% when the water sensitivity occurs. With the same method, the removing rates of C₆H₅OH under the fluid flow and water sensitivity are 55.71% and 43.43% respectively. Supported by National Natural Science Foundation of China (No. 40572142). HAN Zhiyong, born in 1976, male, Dr, associate Prof.     

酯基取代4-苯甲醛缩氨基硫脲衍生物的合成及其生物活性研究

以4-羟基苯甲醛为起始化合物,通过酯化反应在苯甲醛的羟基位置引入不同的酯基得到中间产物(B1-B12),然后在中间产物B1-B12的醛基位置引入氨基硫脲基团,共合成12个酯基取代缩胺基硫脲衍生物(C1-C12)。C1-C12均通过核磁共振氢谱、碳谱、质谱等进行表征。并测试了C1-C12化合物对酪氨酸酶的抑制活性,结果表明大多数酯基取代缩氨基硫脲衍生物对蘑菇酪氨酸酶IC₅₀值小于10 μM,其中抑制活性最强的化合物为C2,其对酪氨酸酶的IC50值达到1.5 μM。随着酯基碳链长度的增加,这类化合物对酪氨酸酶的抑制活性逐渐降低。     

Effects of osmotic stress on antioxidant enzymes activities in leaf discs of P<Subscript>SAG12</Subscript>-<Emphasis Type="Italic">IPT</Emphasis> modified gerbera

Leaf senescence is often caused by water deficit and the chimeric gene PSA612-1PT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance （TBARS） and antioxidant enzymes activities were investigated during leaf senescence of PSA612-1PT modified gerbera induced by osmotic stress compared with the control plant （wild type）. Leaf discs were incubated in 20%, 40% （w/v） polyethylene glycol （PEG） 6 000 nutrient solution for 20 h under continuous light [ 130 μmol/（m^2·s）]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase （SOD）, catalases （CAT）, ascorbate peroxidase （APX）, guaiacol peroxidase （GPX） and dehydroascorbate reductase （DHAR） were stimulated by PEG treatment. However, the increases were higher in PSA612-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation （TBARS content） was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities ofantioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.     

一种新型席夫碱的合成及光谱性质

以1,10-菲罗啉为原料,碱性条件下经氧化生成4,5-二氮杂芴-9-酮,再与2,3-丁二酮双肼腙在醋酸催化下进一步发生反应,生成了一种未见文献报道的氮杂芴酮席夫碱化合物2,3-丁二酮双肼腙双缩（4,5-二氮杂芴-9-酮）,通过核磁、红外、元素分析表征了该化合物的结构,并对其紫外吸收光谱性质进行了研究.     

Synthesis of Novel Ionic Liquid （[C4CNmim]^＋PF6^-） and Application to Preparation of Polyketone

N-valeronitrile-N’-methylimidazolium hexafluorophosphate ([C 4 CNmim]+ PF 6),as a novel ionic liquid with polar nitrile functional group,was prepared.The structure of the ionic liquid was characterized by using IR and 1 H NMR.As a medium,the ionic liquid plays an important role in copolymerization of carbon monoxide (CO) with styrene (St).Some synthetic conditions were determined,including the usage of ionic liquid,palladium composite catalyst and methanol,CO pressure,reaction time and reaction temperature.The influence of these factors on catalytic activity was analyzed.The results show that the catalytic activity has reached 1 724.1 gStCO/(gPd·h) and the catalyst could be reused 5 times under the optimal condition:composite catalyst 0.015 mmol,ionic liquid 3 mL,methanol 0.75 mL,CO pressure 2MPa,reaction time 2 h and reaction temperature 70℃.This CO/St copolymerization within [C 4 CNmim]+ PF 6 system could facilitate ionic liquids with efficient and economical applications to polymeric materials.     

吡啶基苯并咪唑化合物的微波合成及荧光特性

以邻苯二胺、吡啶甲酸为原料,多聚磷酸为催化剂和溶剂,经微波辐射合成了2-（3-吡啶基）苯并咪唑、2-（2-吡啶基）苯并咪唑。通过熔点、元素分析、IR和1H NMR对其纯度和结构进行表征,探讨了目标化合物在微波辐射下合成的工艺条件及荧光特性。     

Neuroanatomy Learning: Augmented Reality vs. Cross-Sections

Neuroanatomy education is a challenging field which could benefit from modern innovations, such as augmented reality (AR) applications. This study investigates the differences on test scores, cognitive load, and motivation after neuroanatomy learning using AR applications or using cross-sections of the brain. Prior to two practical assignments, a pretest (extended matching questions, double-choice questions and a test on cross-sectional anatomy) and a mental rotation test (MRT) were completed. Sex and MRT scores were used to stratify students over the two groups. The two practical assignments were designed to study (1) general brain anatomy and (2) subcortical structures. Subsequently, participants completed a posttest similar to the pretest and a motivational questionnaire. Finally, a focus group interview was conducted to appraise participants’ perceptions. Medical and biomedical students (n = 31); 19 males (61.3%) and 12 females (38.7%), mean age 19.2 ± 1.7 years participated in this experiment. Students who worked with cross-sections (n = 16) showed significantly more improvement on test scores than students who worked with GreyMapp-AR (P = 0.035) (n = 15). Further analysis showed that this difference was primarily caused by significant improvement on the cross-sectional questions. Students in the cross-section group, moreover, experienced a significantly higher germane (P = 0.009) and extraneous cognitive load (P = 0.016) than students in the GreyMapp-AR group. No significant differences were found in motivational scores. To conclude, this study suggests that AR applications can play a role in future anatomy education as an add-on educational tool, especially in learning three-dimensional relations of anatomical structures.     

Effects of low dose of ketotifen and chloroquine combination on the infrastructure of chloroquine resistant strain of Plasmodium yoelii

46 inbred NIH mice were infected by chloroquine resistant strain of Plasmodium yoelii. The ultrastructure changes were observed under the administration of ketotifen(10mg·kg⁻¹·d⁻¹) and chloroquine(10mg·kg⁻¹·d⁻¹) combination and one after another respectively. The effect of taking ketotifen and chloroquine combination showed that parasites died rapidly with a few of intermittent membranes and vacuoles. The effect of taking two kinds of drugs one after another showed that there were exceedingly rich membranes, concentric arrangement structures similar to rough endo-reticulum and conspiciously blocking of the formation of food vacuoles.     

3β，23-二羟基熊果-12-烯-28-醇的合成、表征及抑菌活性研究

积雪草酸（asiaticacid,AA）,是积雪草提取物中的五环三萜烯类组分之一,具有多方面的药理作用,本文以积雪草酸为先导化合物,对积雪草酸C-2位,C-3位和C-28位进行结构修饰获得了积雪草酸衍生物3β,23-二羟基熊果-12-烯-28-醇,借助于IR、1HNMR和13CNMR对相关化合物的结构进行了表征,最后与积雪草酸（AA）、oxacillin（苯唑西林）和norfloxacin（诺氟沙星）三种物质进行了抗菌活性的对比。结果显示：积雪草酸的抑茵活性较好,而目标产物的抑菌活性不明显。     

Purification and some properties of a β-glucanase from a strain,Trichoderma reesei GXC

β-glucanase was purified from a solid-state culture ofTrichoderma reesei on wheat bran in three steps which comprised ammonium sulfate precipitation, Sephadex G-100 chromatography, and DEAE-Sephadex A-50 chromatography. The molecular mass was determined to be 35.21 kilodaltons by sodium dodecyl sulfate-12.5% polyacrylamide gel electrophoresis. The β-glucanase at low pHs was more stable than that at high pHs, and optimum pH was 5.0. The optimum temperature was 60°C, and β-glucanase was relatively stable at below 40°C for 60 min. TheK _m of the enzyme on β-glucan was 10.86 mg/ml, and theV _max on β-glucan was 14286 μmol of glucose equivalents per mg of the pure enzyme per min. The β-glucanase activity was significantly inhibited by Fe³⁺ ions, and was reduced in the presence of Cu²⁺ ions, Mn²⁺ ions and Mg²⁺ ions at 5 mmol/L and 10 mmol/L, respectively. The β-glucanase activity was stimulated by Co²⁺ ions, Ca²⁺ ions, Zn²⁺ ions, and Fe²⁺ ions at 1 mmol/L and 5 mmol/L, respectively. Project supported by Foundation for University Key Teacher of the State Ministry of Education, the National Natural Science Foundation of China (No. 30000118) and Zhejiang Provincial Natural Science Foundation of China (No. 399409).     

The polymerization of methyl methacrylate with a new Tin-bridged yttrocene/Al(I-Bu)3

A new catalyst composed of Tin-bridged yttrocene Ph₂Sn(MeCp)₂YCI (MeCp=methylcyclopentadienyl) and Al (i-Bu)₃ was successfully developed for the polymerization of methyl methacrylate (MMA). Detailed study of factors (such as the molar ratio of Al/Cat., catalyst concentration, various solvents, temperature and time) influencing polymerization reaction indicated that the catalytic active species may be still somewhat stable at high temperature and still have a long catalytic lifetime.¹H NMR spectrum showed about 65% syndiotactic content in the polymethyl methacrylate (PMMA) prepared. From kinetic studies, the polymerization rate equation may be expressed as Rp=Kp[Cat.]^2.4. The overall activation energy of polymerization is 20.9±3.1 kJ/mol. Project(29774021) supported by the Natural Science Foundation of China and National Laboratory of Element-Organic Chemistry, Nakai, University.     

A novel long-chain acyl-derivative of epigallocatechin-3-O-gallate prepared and purified from green tea polyphenols

Lipophilic tea polyphenols (LTP) were prepared by catalytic esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-chain acyl-derivative of epigallocatechin-3-o-gallate (EGCG) was first isolated from purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1∶1∶1∶1, v/v). The molecular structure of the acyl-derivative, Epigallocatechin-3-O-gallate-4′-O-hexadecanate, was elucidated by means of elemental analysis, IR,¹H-NMR and MS spectra. Project (No. 200010) supported by Zhejiang Provincial Natural Science Foundation, China