魔角旋转核磁共振代谢组学方法对镧、铈急性生物效应的比较研究

利用高分辨魔角旋转核磁共振(MAS 1H NMR)技术对腹腔注射不同剂量[2, 10, 50 mg/kg(体重)]的硝酸镧[La(NO3)3]和硝酸铈[Ce(NO3)3] 的雄性Wistar大鼠肝、肾组织的MAS 1H NMR谱进行比较分析, 研究了La(NO3)3和Ce(NO3)3的急性生物效应, 并结合模式识别技术对不同剂量La(NO3)3和Ce(NO3)3的急性生物效应进行了分类. 研究结果表明, La(NO3)3对大鼠的急性毒性主要表现为肝毒, Ce(NO3)3对大鼠肝、肾同时造成损伤. 该方法可用于其它稀土及金属化合物的毒性预测和毒理学研究.     

硝酸镧对长柄扁桃试管苗生根的影响

通过极差分析研究了不同浓度的硝酸镧和生长素组合对长柄扁桃试管苗生根的影响。结果表明:对长柄扁桃生根影响的主次因素为硝酸镧(La(NO3)3)>吲哚丁酸(IBA)>吲哚乙酸(IAA),最优组合为La(NO3)320 mg·L-1+IBA 0.2 mg·L-1+IAA 0.2 mg·L-1。在此条件下培养42 d后,长柄扁桃试管苗根的诱导频率达到89%,平均根长达到9.2 cm,每株根的平均个数为9.7个。对长柄扁桃的根组织活力进行测定,结果表明添加镧的处理组根系还原力是对照(不加镧)组的1.57倍。经过移栽驯化2个月后,长柄扁桃组培苗的移栽成活率达到94%,株高是对照的1.53倍。     

低剂量硝酸镧对小鼠肾脏自由基防御机能的影响

通过采用肾组织匀浆生化测定法, 观察不同剂量硝酸镧灌胃一个月后, 小鼠肾组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、脂质过氧化物(LPO)、谷胱甘肽过氧化物酶(GSH-PX)含量的变化, 探讨了低剂量硝酸镧的抗氧化作用; 结果表明 雌性、雄性小鼠20.0, 10.0 mg*kg-1 Cu-ZnSOD和CAT的含量均较对照组明显降低; 而GSH-Px和LPO的含量均较对照组显著升高. 雌性、雄性小鼠0.1, 0.2, 2.0 mg*kg-1组Cu-ZnSOD, CAT, GSH-Px和LPO的含量与对照组无显著性差异. 较高剂量(20.0, 10.0 mg*kg-1)的硝酸镧的直接损伤可使小鼠肾脏脂质过氧化反应增强, 清除自由基的能力下降. 较低剂量(0.1, 0.2, 2.0 mg*kg-1)的硝酸镧对小鼠肾脏自由基的生成和清除无影响.     

硝酸镧对大鼠肝脏的亚慢性毒性实验研究

以大鼠为对象,连续用生理盐水和20,10,2,0．2,0．1mg.kg^-1La(NO3)3灌胃6个月后,观察了体重,肝体比变化;检测了血清中谷草转氨酶,谷丙转氨酶,碱性磷酸酶和δ－谷氨酰转移酶含量的变化,应用组织化学及透射电镜技术观察了不同剂量La(NO3)3对大鼠肝脏形态结构的影响。20mg/kg^-1La(NO3)3组动物体重增长缓慢,0．1mg.kg^-1La(NO3)3组动物体重增加较快;20mg/kg^-1La(NO3)3组肝脏汇管区有炎细胞浸润,有些肝细胞内有少量的脂滴,糖原减少,线粒体基质密度增高,有电子密度高的致密体,肝细胞核形态正常或轻度变形。     

给药硝酸钕后大鼠完整肝组织及肝组织提取物的NMR代谢组学研究

通过分析不同给药剂量硝酸钕[Nd（NO3）3][2,10,50mg／kg（体重）]后,雄性Wistar大鼠完整肝组织的MAS1HNMR谱和肝组织提取物的^1H NMR谱,结合肝组织病理切片图,研究了稀土化合物Nd（NO3）3在大鼠体内的急性生物效应．利用模式识别方法对给药Nd（NO3）3组和对照组大鼠肝组织^1H NMR谱图数据进行了分析．结果表明,腹腔注射Nd（NO3）3后,大鼠肝脏中甘油三酯、亮氨酸（异亮氨酸）、乳酸、丙氨酸、丙酮酸、磷酸胆碱和葡萄糖含量升高,氮氧三甲胺含量降低．肝脏病理图显示,50mg／kg（体重）组大鼠肝细胞可见微小坏死灶和门管区炎细胞轻度增多．推测硝酸钕能影响大鼠肝脏中能量代谢（糖代谢和脂肪代谢）和氨基酸代谢,对大鼠肝脏造成损伤,且其损伤程度随剂量的增加有增强趋势．     

长期口服硝酸稀土对大鼠腺垂体生长激素细胞的影响

为查明La(NO3)3和农用混合稀土"常乐"长期服用后对大鼠腺垂体中生长激素细胞功能和结构的影响,Wistar大鼠口服不同剂量La(NO3)3和"常乐"后,检测血清中生长激素水平的变化,观察腺垂体中生长激素细胞的超微结构。发现口服6个月后,20mg·kg-1组生长激素水平明显低于对照组,0.2及0.1mg·kg-1组则明显增高;停服1个月后,0.2,0.1mg·kg-1组血清中生长激素水平显著高于对照组。口服6个月后,20mg·kg-1组生长激素细胞内分泌颗粒明显减少,线粒体肿胀,粗面内质网腔明显扩张,细胞核变形;停服1个月后,20mg·kg-1组各种改变有所恢复,0.1mg·kg-1组生长激素细胞分泌颗粒较密集。     

轻稀土镧、铈急性生物效应的血清1H NMR谱代谢组学研究

采用现代核磁共振和模式识别技术,通过分析腹腔注射给药La(NO3)3(2，10和50 mg/kg体重)和Ce(NO3)3(2，10和50 mg/kg体重) 48 h后大鼠血清的核磁共振氢谱,由内源性代谢物浓度的变化研究了两种稀土化合物在大鼠体内的急性生物效应,利用主成分分析法对两者进行了分类比较. 在低剂量(2 mg/kg体重)组La(NO3)3和Ce(NO3)3血清中， 乳酸和肌酸酐等内源性代谢物浓度发生了微小变化； 在高剂量组(10和50 mg/kg体重)中， 含量变化较大的重要内源性代谢物包括3-羟丁酸、丙氨酸、 肌酸酐、 丙酮、 乙酸、 琥珀酸和葡萄糖等,其中3-羟丁酸和丙氨酸等在La的剂量组中变化较大,Ce的剂量组血清中丙酮、 琥珀酸和葡萄糖含量变化明显. 实验结果表明， 低剂量La和Ce的毒性较低,并对机体影响较小,高剂量则对大鼠肝脏造成损伤,且Ce的毒性大于La.     

混合稀土"常乐"对大鼠脾细胞IL-2和γ-IFN的影响

应用脾体比、常规组织学染色观察、淋巴细胞转化率试验及脾细胞IL 2与γ IFN水平的检测研究了不同剂量混合稀土"常乐"灌胃不同时间对大鼠脾脏形态及机能的影响。各剂量组"常乐"灌胃1个月后,大鼠脾体比、脾脏形态结构及免疫功能与对照组无明显差别。"常乐"灌胃6个月后,2,0.2mg·kg-1剂量组可使大鼠脾淋巴细胞转化率升高,2,0.2,0.1mg·kg-1剂量组分泌IL 2水平上升。20,10mg·kg-1剂量组淋巴细胞转化率及IL 2活性与对照组比较无明显差别。     

给药硝酸镨后大鼠尿液和血清的核磁共振代谢组学研究

采用基于核磁共振的代谢组学方法,分析了腹腔注射给药2,10和50 mg/kg体重剂量硝酸镨(Pr(NO3)3) 168 h内Wistar大鼠尿液和血清的核磁共振氢谱.由尿液及血清中内源性代谢物如柠檬酸、琥珀酸、α-酮戊二酸、肌酸酐、N-氧三甲胺、氨基酸、乳酸、牛磺酸及葡萄糖等的浓度变化,并结合大鼠血清指标研究了轻稀土化合物Pr(NO3)3在大鼠体内的急性生物效应.结果表明,Pr(NO3)3急性毒性的靶向器官为肝脏和肾脏,但以肝脏为主,且呈现明显的剂量-反应关系.低、中剂量组的Pr(NO3)3会通过改变大鼠体内酶代谢而造成肝脏线粒体中的能量代谢(脂肪、糖代谢)紊乱;同时,Pr(NO3)3还会影响肾脏的正常功能,改变肾脏中渗透质的平衡,影响肾脏对氨基酸的重吸收和利用.     

镧对水稻磷吸收及其形态的影响

用分根营养液培养法研究了镧对水稻生长, 根、茎、籽粒磷含量, 磷吸收及体内磷形态的影响. 结果表明低浓度镧(0.05～1.5 mg·L-1)提高水稻产量;高浓度镧 (9 mg·L-1～30 mg·L-1) 降低水稻产量. 当镧浓度为0.05～0.75 mg·L-1时, La对水稻茎杆和根干重没有显著促进作用. 在La浓度为6～30 mg·L-1时, 水稻根重显著降低. 镧显著增加根中磷的含量, 降低茎和籽粒中磷的含量, 显著增加根对磷的吸收. 低浓度镧 (0.05～3 mg·L-1) 促进籽粒磷吸收, 而高浓度镧 (6～30 mg·L-1) 减少籽粒磷吸收. 镧显著增加茎和根中络合态磷(EDTA-P)和无机态磷(inorganic-P)含量, 且根中络合态磷和无机态磷的增加占根中总磷增加的80%以上. 当镧浓度为0.05～0.75 mg·L-1, La增加根中核磷(nucleic-P)含量, 而当镧浓度为30 mg·L-1, La降低根中核磷和酯磷(ester-P)含量; La增加根和茎中残渣态磷(residue-P)含量. 文中还讨论了磷的形态与作物磷吸收的关系.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.