Luminescence properties of the co-luminescence groups of Sm-La-pyridyl carboxylic acids

A novel ligand, N,N’-(2,6-pyridinedicarbonyl)bis[N-(carboxymethyl)] (L1) was designed and synthesized starting from pyri-dine-2,6-dicarboxylic acid (1). The ligand (L1) and intermediate product (3) were characterized by 1H nuclear magnetic resonance (NMR), Fourier transform infrared spectrometer (FT-IR) spectra and elemental analysis. Besides, four novel co-luminescence systems of Sm-La-pyridyl carboxylic acids: K4Sm(1-x)Lax(L1)Cl3·y1H2O, K12Sm2(1-x)La2x(L2)3 Cl6·y2H2O, K6Sm2(1-x)La2x(L3)Cl6·y3H2O and K4Sm(1-x)Lax(L4)Cl3·y4H2O (x was the mole fraction of La(III) in the mixed ions, the value was 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, respectively; y1, y2, y3, y4 were plus integer) were studied, and the mechanism of fluorescence enhancement effect was discussed detailedly.     

Rare earth oxide modified Cu-Mn compounds supported on TiO₂ catalysts for low temperature selective catalytic oxidation of ammonia and in lean oxygen

Selective catalytic oxidation(SCO) of ammonia was carried out over Cu-Mn compounds catalysts modified with trivalent rare earth oxide Ce2O3 and La2O3 respectively.TiO2 was used as support and different ratio of O2 were tested in order to find an appropriate O2 concentration(vol.%),and the results showed that 1%O2(vol.%) was propitious to SCO of ammonia.The effects of the two rare earth oxides modified catalysts Ce2O3-Cu-Mn/TiO2 and La2O3-Cu-Mn/TiO2 on the catalytic activity and selectivity of ammonia oxidation were investigated under the reaction condition of 500 ppm ammonia,1%O2(vol.%),at the temperature from 125 to 250 oC.The results revealed the beneficial role of Ce2O3 and La2O3 in catalytic activity at low temperature and lean oxygen concentration,while the modification with Ce2O3 and La2O3 led to the negative influence on N2 selectivity.For the catalysts modified with Ce showed lower NO and N2O selectivity than the catalysts modified with La,then the effects of different Ce loadings on catalytic activity and selectivity were also considered,in combination with catalysts preparation methods,which include incipient wet impregnation,sol-gel method and co-precipitation.Results revealed that the catalysts prepared by sol-gel method obtained preferable catalytic activity compared with the others,reaching 99% ammonia at 200 oC,whereas 96% NO was detected.It also indicated that different catalyst preparation method significantly determined production distribution.     

Effect of rare earth doping on thermo-physical properties of lanthanum zirconate ceramic for thermal barrier coatings

The effect of rare earth doping on thermo-physical properties of lanthanum zirconate was investigated. Oxide powders of various compositions La2Zr2O7 were synthesized by coprecipitation-calcination method. High-temperature dilatometer, DSC, and laser thermal diffusivity methods were used to analyze thermal expansion coefficient （TEC）, specific heat, and thermal diffusivity. The results showed that CeO2 doped pyrochlores La2（Zr1.8Ce0.2）2O7 and La1.7（DyNd）0.15（Zr0.8Ce0.2）2O7 had higher TEC than La2Zr2O7 and La1.7Dy0.3Zr2O7. La2（Zr1.8Ce0.2）2O7, La1.7Dy0.3Zr2O7, and La1.7（DyNd）0.15（Zr0.8Ce0.2）2O7 had lower thermal conductivity than undoped La2Zr2O7. The Dy2O3, Nd2O3, and CeO2 codoped composition showed the lowest thermal conductivity and the highest TEC. Thermo-physical results also indicated that TEC of rare earth oxide doped La2Zr2O7 ceramic was slightly higher than that of conventional ZrO2-8Wt.% Y2O3 （8YSZ）, and its thermal conductivity was lower than that of 8YSZ.     

Mechanism of Effect of Lanthanum Nitrate on Vigor of Aged Rice Seeds

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Postinjury neutrophil priming and activation: an early vulnerable window

BACKGROUND: Generation of extracellular, cytotoxic superoxide anion (O2-) by polymorphonuclear neutrophils (PMNs) contributes to an unbridled inflammatory response that can precipitate multiple organ failure (MOF). Release of O2- is markedly enhanced when activated PMNs have been previously "primed" by inflammatory mediators, such as those expressed after trauma. We therefore hypothesized that PMN priming occurs as an integral part of the early inflammatory response to trauma. METHODS: PMNs were obtained from 17 high-risk patients with torso trauma at 3, 6, 12, 24, 48, and 72 hours after injury, as well as from 10 healthy donors, and the in vitro release of O2- was quantitated with a kinetic, superoxide dismutase (SOD)-inhibitable cytochrome c reduction assay. PMN O2- release was measured in the presence and absence of 1 mumol/L N-formyl-methionyl-leucyl-phenylalanine (fMLP) and after priming and activation with 20 nmol/L platelet-activating factor (PAF) and 1 mumol/L fMLP, respectively. RESULTS: In vitro PMN O2- release was used to determine whether postinjury PMNs were (1) activated in vivo, (2) primed in vivo, or (3) primable in vitro. Unstimulated PMNs from trauma patients spontaneously expressed modest amounts of O2- in vitro from 6 to 48 hours after injury, suggesting endogenous activation. Also, fMLP-activated PMNs collected between 3 and 24 hours after injury expressed more O2- than controls (p < or = 0.02), indicating in vivo, trauma-related priming. Furthermore, postinjury PMNs were maximally primed in vivo (i.e., in vitro exposure to PAF before fMLP activation failed to significantly enhance O2- release) as compared to PMNs treated with fMLP. CONCLUSIONS: These data indicate that major torso trauma (first hit) primes and activates PMNs within 3 to 6 hours after injury. Consequently, we postulate that postinjury priming of PMNs may create an early vulnerable window during which a second hit (e.g., a secondary operation or delayed hemorrhage) activates exuberant PMN O2- release, rendering the injured patient at high risk for MOF.     

Effects of La~（3＋） on osteogenic and adipogenic differentiation of primary mouse bone marrow stromal cells

In order to elucidate the action of La3+ on bone metabolism,effects of La3+ on the osteogenic and adipogenic differentiation of pri-mary mouse bone marrow stromal cells(BMSCs) were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) test,alkaline phosphatase(ALP) activity measurement,mineralized function,oil red O stain and measurement.The results showed that La3+ pro-moted the proliferation of BMSCs except at 1×10-10 and 1×10-6 mol/L.The effect of La3+ on the osteogenic differentiation depended on con-centrations at the 7th day,but the osteogenic differentiation was inhibited at any concentration at the 14th day.La3+ promoted the formation of mineralized matrix nodules except at 1×10-8 and 1×10-5 mol/L.La3+ inhibited adipogenic differentiation except at 1×10-10 and 1×10-7 mol/L at the 10th day,and inhibited adipogenic differentiation except at 1×10-9 mol/L at the 16th day.These findings suggested that La3+ might have protective effect on bone at appropriate dose and time.This would be valuable for better understanding the mechanism of the effect of La3+ on bone metabolism.     

等离子喷涂双相复合结构顶层热障涂层的研究

热障涂层 (TBCs) 是燃气轮机等设备的高温部件上不可缺少的防护技术。 La2Zr2O7 是最具潜力的顶层材料, 但其韧性差等问题限制了其应用。 本研究采用双相复合陶瓷技术对 La2Zr2O7 进行改性, 以 LaPO4 与 La2Zr2O7 的 双相复合材料为热障涂层顶层材料。 采用机械混合和喷雾造粒技术制备双相陶瓷材料, 利用等离子喷涂的方法制 备双相陶瓷顶层。 通过热循环和冲蚀实验检测双相复合涂层的性能。 利用 X 射线衍射仪 (XRD) 检测涂层的相结构, 利用扫描电镜(SEM)检测涂层的表面和剖面形貌。结果表明, 双相复合结构涂层表面微细裂纹增多, 粗大裂纹减少, 裂纹会产生曲折和分叉。 LaPO4 的加入提高了双相陶瓷材料的韧性和断裂强度, 和单相 La2Zr2O7 涂层相比, 双相 陶瓷涂层在冲蚀过程中失重较少。     

Effect of Rare Earths on Mechanical Properties and Microstructures of Si3N4-based Ceramics

Si3N4-hased ceramics exhibit excellentproperties such as high strength, high corro..sion resistance, high fire resisting property andhigh thermal shock resistance. However, up tonow, the application of St3N4-based ceramicsis still limited by their poor ductility, lowtoughness and stability. Adding fiber or whisher into ceramic matrix is a useful tougheningmethod, but fiber and whisker are costly and itis difficult to homogenize them in ceramic matrix. Furthermore, ceramic powders can not fill…     

Lactate and PO2 modulate superoxide anion production in bovine cardiac myocytes: potential role of NADH oxidase

BACKGROUND: Lactate increases lucigenin chemiluminescence (CL)-detectable superoxide anion (O2.-) generation in bovine vascular smooth muscle and endothelium, and a microsomal flavoprotein-containing NADH oxidase whose activity is regulated by PO2 and cytosolic NAD(H) redox appears to be the detected source of O2.- production. Little is known about the importance of this O2.(-)-producing system in cardiac myocytes. METHODS AND RESULTS: In isolated bovine cardiac myocytes, lactate (10 mmol/L) increased lucigenin-detectable O2.- levels to approximately 1.8 times baseline, whereas pyruvate (10 mmol/L) and mitochondrial probes did not increase the detection of O2.-. A nonmitochondrial NADH oxidase activity, found in microsomes containing a cytochrome b558, was a major source of O2.- production in the homogenate of myocytes, because NADH (0.1 mmol/L) increased basal lucigenin CL >100-fold. NADPH oxidases, mitochondria, and xanthine oxidase were minor sources of detectable O2.- production. However, mitochondria released H2O2 in the presence of 5 mmol/L succinate and 30 micromol/L antimycin, based on its detection as catalase-inhibitable luminol (+horseradish peroxidase)-elicited CL. Diphenyliodonium (DPI), an inhibitor of flavoprotein-containing oxidases, significantly attenuated basal, lactate, and NADH-elicited lucigenin CL. Hypoxia eliminated myocyte lucigenin CL, and posthypoxic reoxygenation caused an 8.6-fold increase in the detection of O2.- that was potentiated by lactate and inhibited by DPI. CONCLUSIONS: NADH oxidase activity linked to cytosolic NAD(H) redox appears to be a key source of O2.- production in cardiac myocytes that could contribute to oxidant signaling mechanisms and injury upon exposure to changes in PO2 and metabolites produced under hypoxia, such as lactate. These processes could contribute to the previously observed potentiation of injury caused by lactate in cardiac ischemia/reperfusion.     

Superoxide generation links protein kinase C activation to impaired ATP-sensitive K+ channel function after brain injury

BACKGROUND AND PURPOSE--Endothelin-1, in concentrations similar to that present in cerebrospinal fluid after fluid percussion brain injury (FPI), increases superoxide anion (O2-) production. Endothelin-1 also contributes to altered cerebral hemodynamics after FPI through impairment of ATP-sensitive K+ (KATP) channel function through protein kinase C (PKC) activation. Generation of O2- additionally occurs after FPI. Nitric oxide and cGMP elicit pial artery dilation through KATP channel activation. The present study was designed to determine whether PKC activation generates O2-, which, in turn, could link such activation to impaired KATP channel function after FPI. METHODS--Injury of moderate severity (1.9 to 2.1 atm) was produced by the lateral FPI technique in anesthetized newborn pigs equipped with a closed cranial window. Superoxide dismutase-inhibitable nitroblue tetrazolium (NBT) reduction was determined as an index of O2- generation. RESULTS--Phorbol 12, 13-dibutyrate (10(-6) mol/L), a PKC activator, increased superoxide dismutase-inhibitable NBT reduction from 1+/-1 to 37+/-5 pmol/mm2. Staurosporine (10(-7) mol/L), a PKC antagonist, blocked the NBT reduction after phorbol 12,13-dibutyrate and blunted the NBT reduction observed after FPI (1+/-1 to 15+/-2 versus 1+/-1 to 5+/-1 pmol/mm2 after FPI in the absence versus presence of staurosporine). Exposure of the cerebral cortex to a xanthine oxidase O2--generating system increased NBT reduction in a manner similar to FPI and blunted pial artery dilation to the KATP channel agonists cromakalim and calcitonin gene-related peptide, the nitric oxide releasers sodium nitroprusside and S-nitroso-N-acetylpenicillamine, and the cGMP analogue 8-bromo-cGMP (10+/-1% and 21+/-1% versus 4+/-1% and 9+/-1% for 10(-8) and 10(-6) mol/L cromakalim before and after activated oxygen-generating system exposure). CONCLUSIONS--These data show that PKC activation increases O2- production and contributes to such production observed after FPI. These data also show that an activated system that generates an amount of O2- similar to that observed with FPI blunted pial artery dilation to KATP channel agonists and nitric oxide/cGMP. These data suggest, therefore, that O2- generation links PKC activation to impaired KATP channel function after FPI.     

Lanthanum(Ⅲ) sorption studies on poly[dibenzo-18-crown-6] and its separation from uranium(Ⅵ) and thorium(Ⅳ) in L-valine medium

The sorption study of La(Ⅲ) was carried out on poly[dibenzo-18-crown-6] and L-valine medium. The quantitative adsorption of La(Ⅲ) was found at 1x10-2 to 1x10-5 mol/L L-valine. The various eluting agents were found efficient eluents for La(Ⅲ). The capacity of crown polymer for La(Ⅲ) was found to be 0.43 ±0.01 mmol/g. The tolerance limit of various cations and anions for La(Ⅲ) was determined.La(Ⅲ) was quantitatively separated from other metal ions in binary as well as multicomponont mixtures. The study was extended to sequen-tial separation of La(Ⅲ), U(Ⅵ) and Th(Ⅳ). The good separation yields were obtained and had good reproducibility (±2%). The method in-corporated the determination of La(Ⅲ) in real sample. The method was simple, rapid and selective.     

Diagnosis of a case of acute chloroquine poisoning using 1H NMR spectroscopy: characterisation of drug metabolites in urine

The compromised optima for high intensity chemiluminescence (CL), using superoxide generators, were all above pH 9.0 for the CL probes luminol and lucigenin. With luminol the optima were at pH 9.0 and 9.4 for the generators KO2 and hypoxanthine/xanthine oxidase (HX/XO), respectively. Lucigenin, with the same generators, produced optima at pH 9.5 and 10.0, respectively. The probe methyl-Cypridina-luciferin analogue (MCLA) produced optima closer to neutral pH, which is preferred for physiological assessments. MCLA had optima at pH 6.0, 8.7 and 9.5 with KO2 and with HX/XO optima at pH 4.8, 6.0, 7.0 and 8.7. When CL was assessed at physiological pH, MCLA observed superoxide radicals with a sensitivity of 100- and 330-fold more than luminol or luicigenin respectively. For singlet oxygen, the sensitivity of MCLA at this pH was 45- and 5465-fold more than for the said probes respectively. H2O2 did not elicit CL between pH 4 and 9.5 with any of the probes and did not influence the production of superoxide or singlet oxygen when co-assessed. Therefore CL could only be obtained when enzymes were used as converters. The optima for the enzyme-conversion system horseradish peroxidase (HRP)/H2O2, and luminol, were at pH 8.0 and 9.2. Lucigenin and HRP/H2O2 also had a biphasic CL profile with optima at pH 7.4 and 9.6. MCLA and HRP/H2O2 had five optima, with the major ones at pH 6.1 and beyond 10. The optima for the myeloperoxidase/H2O system were at 8.6 and beyond 10.0 when luminol and 0.15 mol/L NaBr were used.     

Thermal conductivity of （Sm1-xLax）2Zr2O7 （x=0, 0.25, 0.5, 0.75 and 1） oxides for advanced thermal barrier coatings

Pyrochlore oxides of general compositions, A2Zr2O7, where A is a 3+ cation (La to Lu), are promising candidate materials for ap-plications as high temperature thermal barrier coatings because of their high melting points, high thermal expansion coefficients, and low thermal conductivities. In this study, oxides of Sm2Zr2O7, (Sm0.75La0.25)2Zr2O7, (Sm0.5 La0.5)2Zr2O7, (Sm0.25La0.75)2Zr2O7 and La2Zr2O7 were prepared by solid reactions at 1600 ℃ for 10 h using Sm2O3, La2O3 and ZrO2 as the reactants. The phase compositions of these ceramic ma-terials were analyzed by X-ray diffractometer (XRD) and fourier transform infrared spectroscopy (FT-IR) methods, respectively. The micro-structure was observed by scanning electronl microscope (SEM). The thermal conductivities of these ceramic materials were measured using laser-flash method. XRD and FT-IR results showed that pure ceramic materials with pyrochlore structure were prepared successfully. SEM results indicated that microstructures of these ceramic materials were dense and grain boundaries were very clean. The La2O3 doped Sm2Zr2O7 pyrochlores (Sm0.75 La0.25)2Zr2O7 and (Sm0.5 La0.5)2Zr2O7 had lower thermal conductivity than the undoped Sm2Zr2O7. The thermal conductivity of (Sm0.25La0.75)2Zr2O7 was found to be lower than that of La2Zr2O7. The results showed that these ceramic materials had the poten-tial to be used as candidate materials for TBCs.     

La2O3在空气中稳定性的研究

通过对 L a2 O3 粉末在空气中吸水的增重测定及增重前后的 X射线衍射结构分析 ,发现 L a2 O3 吸水之后转变成 L a(OH) 3 。因此 ,L a2 O3 是一种化学性质不稳定的化合物 ,从前文献中关于“L a2 O3 是一种化学性质稳定的氧化物”的观点值得商榷。     

Superoxide anion production in influenza protein-activated NADPH oxidase of human polymorphonuclear leukocytes

There are conflicting reports regarding superoxide anion (O2-) production by human polymorphonuclear leukocytes (PMNL) that have been activated by influenza virus. In the present study, the output of O2- was determined by measuring superoxide dismutase-inhibitable cytochrome c reduction. Incubation of PMNL with purified influenza matrix (M) protein, neuraminidase (NA), or hemagglutinin (HA) enhanced the production of O2-: 4.93 nmol of O2-/4 x 10(5) cells/15 min was produced with M protein, 5.20 with NA, and 6.89 with HA. These values were significantly higher (P < .05) than that for untreated PMNL (1.51). Both nonglycosylated and glycosylated proteins had the potential to generate O2- in human PMNL. Neither the hemagglutinating activity of HA nor the enzymatic activity of NA were necessary for viral protein activation of PMNL.     

Synthesis, Characterization and Fluorescence Properties of Europium, Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.     

Redox modulation of L-type calcium channels in ferret ventricular myocytes. Dual mechanism regulation by nitric oxide and S-nitrosothiols

The effects of NO-related activity and cellular thiol redox state on basal L-type calcium current, ICa,L, in ferret right ventricular myocytes were studied using the patch clamp technique. SIN-1, which generates both NO. and O2-, either inhibited or stimulated ICa,L. In the presence of superoxide dismutase only inhibition was seen. 8-Br-cGMP also inhibited ICa,L, suggesting that the NO inhibition is cGMP-dependent. On the other hand, S-nitrosothiols (RSNOs), which donate NO+, stimulated ICa,L. RSNO effects were not dependent upon cell permeability, modulation of SR Ca2+ release, activation of kinases, inhibition of phosphatases, or alterations in cGMP levels. Similar activation of ICa,L by thiol oxidants, and reversal by thiol reductants, identifies an allosteric thiol-containing "redox switch" on the L-type calcium channel subunit complex by which NO/O2- and NO+ transfer can exert effects opposite to those produced by NO. In sum, our results suggest that: (a) both indirect (cGMP-dependent) and direct (S-nitrosylation/oxidation) regulation of ventricular ICa,L, and (b) sarcolemma thiol redox state may be an important determinant of ICa,L activity.     

Influence of La, Y, Gd, Cu, NH4^＋ Ions and DMSO on Luminescent Property of Terbium Complexes with Sulfosalicylate

Ｔｈｅｌａｎｔｈａｎｉｄｅｃｏｍｐｌｅｘｅｓｏｆｏｒｇａｎｉｃｌｉｇ ａｎｄｓａｓｆｌｕｏｒｅｓｃｅｎｔｍａｔｅｒｉａｌｓｈａｖｅｒｅｃｅｉｖｅｄｅｘ ｔｅｎｓｉｖｅａｔｔｅｎｔｉｏｎ .Ｔｈｅｕｓｅｏｆｆｌｕｏｒｅｓｃｅｎｔｏｒｇａｎｏ ｌａｎｔｈａｎｉｄｅｃｏｍｐｌｅｘｅｓｒｅｑｕｉｒｅｈｉｇｈｆｌｕｏ ｒｅｓｃｅｎｃｅｉｎｔｅｎｓｉｔｙａｎｄｌｏｗｃｏｓｔｃｏｍｐｌｅｘｅｓ .Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｔｈｅｆｌｕｏｒｅｓｃｅｎｃｅｅｎｈａｎｃｅｍｅｎｔｏｆＴｂ(Ⅲ )ｏｒＥｕ(Ⅲ )ｃｏｍｐｌｅｘｅ…     

Direct effects of intraperilymphatic reactive oxygen species generation on cochlear function

Reactive oxygen species (ROS) generation may play a role in ototoxicity, however, the specific effects of ROS generation upon cochlear function are unstudied. Therefore, guinea pig cochleas were instilled with artificial perilymph (AP), H2O2, or confirmed generating systems for the superoxide anion (O2-) or the hydroxyl radical (OH.), or with an ROS system plus its respective scavenger -catalase (CAT), superoxide dismutase (SOD) or deferoxamine (DEF). O2- generating system instillation led to significantly greater mean high frequency compound action potential (CAP) threshold shifts at 10 and 120 min post infusion than seen in AP control or SOD/O2- groups. H2O2 group CAP threshold shifts were significantly greater than control and CAT/H2O2 group values at 10 (16-30 kHz), and 120 min (above 12 kHz). OH generating system instillation led to significantly greater CAP threshold shifts at 10 (12-30 kHz) and 120 min (above 6 kHz) than seen in control or DEF/OH groups. No significant CAP differences were found between controls and scavenger/ROS groups. Mean 1.0 microV cochlear microphonic isopotential curve shift values did not systematically differ among groups. The rapid degradation of high frequency CAP threshold sensitivity seen here may provide insight into the portion of cochlear dysfunction which is ROS-mediated following noise, radiation or chemical exposures.