Magnetic properties and magnetic entropy changes of MRE_2Co_7 compounds

(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds for magnetic refrigeration were studied by X-ray diffraction, ac susceptibility and isothermal magnetization measurements. X-ray powder diffraction shows that all the compounds have hexagonal Ce2Ni7-type structure. The Curie temperatures(TC) are 258 K and 222 K for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. High coercivities(HC) of about 1.74 and 6.61 k Oe at 5 K with a smooth demagnetization curves were obtained for the(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. For an applied field change from 0 to 50 k Oe, the maximum(??SM) for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds are 0.52 and 0.67 J/(kg K), respectively.     

九里香叶中甲氧基黄酮类化合物的NMR研究

从九里香(Murraya exotica L.)叶中分离得到三个甲氧基黄酮类化合物：5,7,3′,4′-四甲氧基黄酮(化合物1)、5,7,3′,4′,5′-五甲氧基黄酮(化合物2)和5,6,7,3′,4′,5′-六甲氧基黄酮(化合物3). 应用1D和2D NMR(包括¹H-¹H COSY、HMQC和HMBC)对这三种化合物的结构进行了分析,确认了三个化合物中甲氧基的连接位置,并对¹H和¹³C化学位移进行了归属.     

(Nd1-xErx)3Fe273Ti17化合物的结构与磁性

通过x射线衍射分析和磁性测量对(Nd1-xErx)3Fe273Ti17化合物的结构与磁性进行了研究.单相(Nd1-xErx)3Fe273Ti17化合物的成相范围为x=00—05之间，所有化合物均属于单斜晶系、Nd3(Fe,Ti)29型结构和A2/m空间群.着Er含量的增加，(Nd1-xErx)3Fe273Ti17化合物的晶胞体积、居里温度TC和5K下的饱和磁化强度Ms均单调减小，而5K下的饱和磁化强度Ms和Er含量的关系与稀释模型所描述的结果相一致.(Nd1-xErx)3Fe273Ti1 关键词： (Nd1-xErx)3Fe273Ti17化合物 磁晶各向异性 自旋重取向 磁相图     

[Mo3S7]分子簇和聚合簇合物的振动光谱和电子光谱

本文报道了分立簇「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」１及它的四聚物｛「Ｍｏ３ＳＵ（ｄｔｐ）３」４Ｉ｝．｛（ＨｇＩ３）４．Ｋ｝２（ｄｔｐ＝Ｓ２Ｐ（ＯＣ２Ｈ５）＾－２的ＩＲ,Ｒａｍａｎ和ＵＶ－Ｖｉｓ光谱,并讨论分立的「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」在四聚后这些光谱的变化。     

Syntheses and X-ray excited luminescence properties of Ba3BP3O12 , BaBPO5 and Ba3BPO7

Ba₃BP₃O₁₂, BaBPO₅ and Ba₃BPO₇ have been synthesized by the solid-state reaction method. The X-ray-excited luminescent properties of these compounds were investigated, all of these compounds show broad emission band with the peak center at about 400 nm. The room temperature fluorescent decay of these compound powders was measured. Compared to the other two compounds, Ba₃BPO₇ has the maximum emission intensity while Ba₃BP₃O₁₂ has the fastest decay time with 56.3 ns(99.7%). Combining with the X-ray excited luminescent spectra and fluorescent decay profiles of these compounds, it is supposed that all of these compounds should correspond to two different luminescent mechanisms; the luminescent mechanisms of these compounds were discussed. The potential applications of these compounds are pointed out.     

Antitumor evaluation and 3D-QSAR studies of a new series of the spiropyrroloquinoline isoindolinone/aza-isoindolinone derivatives by comparative molecular field analysis (CoMFA)

In current study, antitumor activity of two series of the newly synthesized spiropyrroloquinoline isoindolinone and spiropyrroloquinoline aza-isoindolinone scaffolds was evaluated against three human breast normal and cancer cell lines (MCF-10A, MCF-7 and SK-BR-3) and compared with cytotoxicity values of doxorubicin and colchicine as the standard drugs. It was found that several compounds were endowed with cytotoxicity in the low micromolar range. Among these two series, compounds 6i, 6j, 6k and 7l, 7m, 7n, 7o containing 3-ethyl-1H-indole moiety were found to be highly effective against both cancer cell lines ranging from \(0.080 \pm 0.001\) to \(11.91 \pm 1.39\,\upmu \hbox {M}\) in comparison with the corresponding analogs. Compared with human cancer cells, the most potent compounds did not show high cytotoxicity against human breast normal MCF-10A cells. Generally, most of the evaluated compounds 6a–l and 7a–o series showed more antitumor activity against SK-BR-3 than MCF-7 cells. Moreover, comparative molecular field analysis (CoMFA) as a popular tools of three-dimensional quantitative structure–activity relationship (3D-QSAR) studies was carried out on 27 spiropyrroloquinolineisoindolinone and spiropyrroloquinolineaza-isoindolinone derivatives with antitumor activity against on SK-BR-3 cells. The obtained CoMFA models showed statistically excellent performance, which also possessed good predictive ability for an external test set. The results confirm the important effect of molecular steric and electrostatic interactions of these compounds on in vitro cytotoxicity against SK-BR-3.     

XRD,XPS, SEM/EDX and broadband impedance spectroscopy study of pyrophosphate (LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7) ceramics

LiFeP₂O₇ and Li_0.9Fe_0.9Ti_0.1P₂O₇ were synthesised by solid-state reaction and ceramics were sintered. The structure of compounds was studied in the temperature range 300–700 K by X-ray diffraction. Ceramics’ surfaces were investigated by scanning electron microscope. Binding energies of Fe 2p, P 2p and O 1s core levels at ceramics’ surfaces have been determined by X-ray photoelectron spectroscopy and different valence states of Fe and P were detected. Elemental compositions of the compounds were studied by energy dispersive X-ray spectrometer. Impedance spectroscopy was performed in the frequency range 10 Hz–3 GHz and in the temperature interval 400–700 K. The changes of the activation energy of ionic conductivity at 528 and 550 K for LiFeP₂O₇ and Li_0.9Fe_0.9Ti_0.1P₂O₇, respectively, were found. The phenomena can be related to disordering in the unit cells of the compounds.     

Spectral-Luminescent Properties and Molecular Orbital Treatment of Some Mono- and Difluoroquinolones

Electronic absorption and luminescent spectra of nonfluorinated nalidixic (nlqH) and pipemidic acid (pifqH), monofluoroquinolones – norfloxacin (nfqH) and pefloxacin (pfqH) as well as of their difluorinated analogs 1-ethyl-6,8-difluoro-1,4-dihydro-7-(1-(4-methylpiperazinyl) – 4-oxo-3-quinolinecarboxylic (mdfqH) acid and 1-ethyl-6,8-difluoro-1,4-dihydro-7-(1-piperazinyl) – 4-oxo-3-quinolinecarboxylic acid (dfqH) - were investigated. Quantum yields, lifetimes of excited states and rate constants of radiative and nonradiative transitions of the compounds were measured. The Mulliken charges of atoms from these compounds were calculated by quantum-chemical complex GAMESS. Differences in the electronic structures of these compounds and their spectral-luminescent characteristics were compared with the data of the phototoxicity degree of fluoroquinolones. Analysis of the Mulliken charges of the difluoroquinolones points to the changes of the redistribution of the electron density along π-conjugated system, and on the oxygen atoms of the carbonyl and carboxyl groups. The analysis of the molecular orbitals involved in the electronic transitions of the compounds revealed that both defluorination and piperazine photolysis are photodecomposition mechanisms which may take place in the excited states of these compounds. The relationship between the location order of the π-π* excited levels of the FQs and the degree of their phototoxicity has been determined     

Versatile Nitro-Fluorophore as Highly Effective Sensor for Hypoxic Tumor Cells: Design, Imaging and Evaluation

Based on the characteristics of a nitro-group, which can be partially or totally reduced to an amino-group in hypoxic cells, two series of hypoxic sensors containing 7H-Benzimidazole [2,1-a]benz[de]isoquinolin-7-one cores with nitro groups in different positions were designed, synthesized and evaluated. The target compounds exhibited significantly different fluorescence characteristics (fluorescence enhancement or quenching). The strong fluorescences of some partially reduced compounds could be explained through the examination of their infrared spectra, which showed a restriction of the nitro-group vibration. These compounds exhibited significant hypoxic–oxic fluorescence differences not only in numerical values but also in their fluorescent imaging properties as reported for the first time.      

铁掺杂GdBa_2Cu_3O_7的化学键性质和Mossbauer谱研究

利用电介质的平均能带模型计算了 Gd Ba2 Cu3O7的化学键参数 ,得到 Cu(1 ) - O键的平均共价性为 0 .41 6,Cu(2 ) - O键的平均共价性为 0 .2 8。应用由共价性和极化率定义的化学环境因子计算了 57Fe在 Gd Ba2 Cu3O7中的 Mossbauer同质异能位移 ,确定了 57Fe在 Gd Ba2 Cu3O7中的价态和占位情况。     

Chemical carcinogenesis studies in nonhuman primates

This review covers chemical carcinogenesis studies in nonhuman primates performed by the National Cancer Institute, USA, to provide hitherto unavailable information on their susceptibility to compounds producing carcinogenic effects in rodents. From autopsy records of 401 breeders and untreated controls, incidences of spontaneous malignant tumors were found to be relatively low in cynomolgus (1.9%) and rhesus monkeys (3.8%), but higher in African green monkeys (8%). Various chemical compounds, and in particular 6 antineoplastic agents, 13 food-related compounds including additives and contaminants, 1 pesticide, 5 N-nitroso compounds, 3 heterocyclic amines, and 7 "classical" rodent carcinogens, were tested during the 34 years period, generally at doses 10 approximately 40 times the estimated human exposure. Results were inconclusive in many cases but unequivocal carcinogenicity was demonstrated for IQ, procarbazine, methylnitrosourea and diethylnitrosamine. Furthermore, negative findings for saccharine and cyclamate were in line with results in other species. Thus susceptibility to carcinogens is at least partly shared by nonhuman primates and rodents.     

亚磷酸二烷基酯及其汞化物的光解活泼自由基的ESR研究

本文用自旋捕捉技术和ESR方法,对亚磷酸二烷基酯(RO)₂P(O)H(R=C₂H₅,n-C₃H₇,i-C₃H₇,n-C₄H₉)及其汞化物(RO)₂ P(O)HgX(X=OAc,Cl,Br)的光解产物进行了研究。结果表明,亚磷酸二烷基酯的汞化物比亚磷酸二烷基酯更容易产生自由基(RO)₂p(O)。据此对汞化物中P-Hg的成键特征进行了讨论。     

虎皮楠中2个黄酮苷的波谱学研究

研究了虎皮楠中的抗氧化活性成分.应用D101大孔吸附树脂、Sephadex LH-20及制备型高效液相色谱进行分离,应用波谱学(UV,ESI-MS,1H NMR,13C NMR,1H-1H COSY,HSQC,HMBC等)方法进行结构鉴定.分离得到1个二氢黄酮苷类化合物和1个黄酮苷类化合物,确定了1H NMR,13C NMR信号的全归属,化合物1鉴定为5,4′-二羟基二氢黄酮-7-O-α-L-鼠李糖(1→2)-β-D-葡萄糖苷,化合物2鉴定为7,4′-二羟基异黄酮-8-C-β-D-葡萄糖碳苷.     

Synthesis of novel 7-aryl and 7-spiropyrazolo[4′,3′:5,6]pyrido[2,3-<Emphasis Type="BoldItalic">d</Emphasis>]pyrimidine derivatives and their study as AChE inhibitors

An efficient route for the synthesis of novel 7-aryl and 7-spiropyrazolo[4\(^{\prime }\),3\(^{\prime }\):5,6]pyrido[2,3-d]pyrimidine derivatives is described. These compounds were obtained by a cyclocondensation reaction between pyrazolopyridinediamines 4 and aldehydes 5 or cyclic ketones 6 in the presence of acetic acid as catalyst. This procedure provides the desired compounds in good yields under a simple two-step methodology. The obtained compounds were evaluated as AChE inhibitors and showed weak AChe inhibition with \(\hbox {IC}_{50} = 115{-}470 \, \upmu \hbox {M}\).     

蕤核挥发油化学成分的分析

采用普通水蒸气蒸馏法提取蕤核挥发油,通过气相色谱-质谱(GC-MS)联用技术进行分析鉴定,共鉴定出33种化学组分,占挥发油总量的78.038%.主要含有斯巴醇(10.265%),亚油酸(8.075%),β-石竹烯(7.278%),7-辛烯-4-醇(6.572%),枯茗醛(4.435%),α-非兰烯醇(4.093%)等。     

射干中一个新异黄酮的核磁共振研究

从射干中分离得到一个新异黄酮及结构相似的两个异黄酮类化合物,即 5,7,3′-三羟基-6,2′,5′-三甲氧基异黄酮, 5,7,3′-三羟基-6,4′,5′-三甲氧基异黄酮（野鸢尾黄素）和它的苷（野鸢尾苷）. 它们的结构都通过¹H NMR, ¹³C NMR 确定. 新异黄酮的结构通过MS, HMBC, HSQC 和 NOESY进一步确定.     

Novel antimitotic agents related to tubuloclustin: synthesis and biological evaluation

Tubuloclustin [N-(7-adamant-2-yloxy-7-oxoheptanoyl)-N-deacetylcolchicine], a highly cytotoxic anti-tubulin compound is known for its ability to promote microtubule disassembly followed by the formation of tubulin clusters of unique morphology. Three series of antimitotic agents related to tubuloclustin were designed and synthesized in order to enhance the molecular diversity of “tubuloclustin-like” family of compounds. The series of compounds with modified adamantane moiety was highly potent in cytotoxic effect on human lung carcinoma A549 cells (EC50 = 6–400 nM) and was active in affecting the microtubule arrays and induction of strong tubulin clusterization. In two other sets of compounds, the colchicine moiety of tubuloclustin was replaced by podophyllotoxin or combretastatin A-4. All combretastatin A-4 derivatives displayed noticeable cytotoxic activity (\(\hbox {EC}50=0.8{-}1.6\,\upmu \hbox {M}\)) but their effect on microtubules depended on the position of the linker attachment. Podophyllotoxin derivatives were also toxic to A549 cells (\(\hbox {EC}50=0.38{-}0.50\,\upmu \hbox {M}\)) and caused both microtubule depolymerization and some tubulin clustering. The data obtained gave additional evidence that the whole panel of C7-colchicine, podophyllotoxin and combretastatin derivatives could manifest clustering effect, and the strength of this effect correlated with cytotoxic activity of the compounds.     

鹅绒藤地上部分的化学成分

研究鹅绒藤地上部分水提物的化学成分.应用硅胶柱层析技术,薄层层析技术,凝胶柱层析技术,重结晶技术进行分离纯化以及应用MS,NMR技术进行结构鉴定.分离得到4个化合物,分别为A:7-O-α-L-鼠李吡喃糖基-山奈酚-3-O-α-L-鼠李糖苷,B:正三十三烷醇,C:正三十八烷,D:胡萝卜苷.化合物B,C,D为首次从该植物中...     

Molecular Modeling and Design of Arylthioindole Derivatives as Tubulin Inhibitors

对一系列具有抗人乳腺癌细胞系MCF-7生物活性的微管蛋白抑制剂─芳基硫代吲哚衍生物(arylthioindole),进行了三维定量构效关系(3D-QSAR)和对接(docking)研究. 在训练集中,建立了具有良好统计质量和预报能力的比较分子力场分析(CoMFA) 模型,其非交叉验证相关系数平方R₂为0.898,交叉验证相关系数平方q₂为0.654. 同时在测试集的验证中得到预测相关系数平方R₂(pred)为0.816, 进一步表明了该模型具有较高的预测能力. 此外,通过对接研究,获得了这些化合物与微管蛋白作用的键合方式和构象,发现该系列化合物的CoMFA力场分布与对接结合位点上的三维拓朴结构相一致. 根据CoMFA和对接分析的结果,细致地讨论和总结了有利于提高或改进该类化合物活性的主要因素,即在取代基R3、R4和R5上引进高电负性的基团,在取代基R6上引进带有高电负性且大体积的基团,以及在取代基R7上引进小体积的基团等都是有利的. 基于这些研究结果,在理论上还设计了5个新的具有较高活性的化合物.     

Synthesis of Amide Compounds of Ferulic Acid and Their Association with Bovine Serum Albumin

ABSTRACT

In this work, three new amide compounds of ferulic acid (FA) were synthesized. The fluorescence and ultraviolet spectroscopy were explored to study the interactions between three amide compounds of FA and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results showed that the fluorescence quenching mechanism between BSA and three amide compounds of FA were mainly static quenching and nonradiation energy transfer at 25°C, 30°C, and 37°C. The Stern–Volmer quenching constants, the binding constants, and the number of binding sites and corresponding thermodynamic parameters ΔH, ΔG, and ΔS were calculated at different temperatures. From the thermodynamic parameters, we concluded that the action force was mainly a hydrophobic interaction. According to the F?rster theory of nonradiation energy transfer, the binding distances (r) between BSA and amide compounds are less than 7 nm. Furthermore, the effects of amide compounds on the conformation of BSA were analyzed using synchronous fluorescence spectroscopy.