Co_3(CO)_7(μ_3-S)(μ,η~2-SCNR_2)的合成和晶体结构

Co2 (CO) 8 与 4个二硫代双 (烷基硫代甲酰胺 )类前配体 [R2 NC(S) S]2 反应 ,得 4个含烷基硫代甲酰胺基的三核钴羰基硫簇合物 .通过元素分析、IR、 1H NMR和 MS等方法表征了它们的结构 ,用 X射线衍射法测定了其中一个簇合物 Co3 (CO) 7(μ3 - S) [μ,η2 - SCN(i- Pr) 2 ]( )的晶体结构 .晶体属单斜晶系 ,P2 1/n空间群 ,晶胞参数 a=1.1452 (2 ) nm,b=1.50 2 8(3) nm,c=1.2 144 (2 ) nm,α=90°,β =92 .15(3)°,γ =90°,V =2 .0 885(7) nm3 ,Z=4 ,F (0 0 0 ) =10 96 ,Dc=1.74 7mg· m-3 ,GOF(F2 ) =0 .835,μ=2 .588nm-1.最终因子 R[I>2 σ(I) ]=0 . 0 4 0 7,Rw=0 .0 6 2 4

A BIS(2,6-DI-TERT-BUTYL-4-METHYLPHENOLATO)-SAMARIUM(II) COMPLEX, [SM(OAR)2(THF)3]-THF

The title complex, bis(2,6-di-tert-butyl-4-methyl-phenolato-O)tris(tetrahydrofuran-O)samarium tetrahydrofuran solvate, [Sm(C15H23O)2(C4H8O)3].C4H8O, has distorted trigonal bipyramidal geometry around the Sm(II) atom. The 0(2), 0(3) and 0(4) atoms of the

~(13)C-NMR化学位移与聚合物的构象——Ⅱ.1,2-聚丁二烯仲碳(—CH_2—)的~(13)C-NMR谱研究

在1,2-聚丁二烯链分子中,导致仲碳(—CH_2—)谱峰分裂的原因是存在着两种gauche排列。在这样一个复杂体系中,由于主链仲碳与叔碳的gauche排列占有重要的位置,因此主链叔碳对化学位移的贡献对于仲碳谱有着决定性的影响。相比之下,乙烯基的贡献要小得多。两种贡献分别是γ_1=—6.37——6.41ppm与γ_2=0.0——1.56ppm。在不计入侧基的影响或同时考虑乙烯基的贡献这两种情况下,均方误差MSE分别是0.166×10~(-2)和0.364×10~(-2)ppm~2。本文同时讨论了模型链的种类、链长以及温度对键概率的影响。并指出有个别反常的情况发生。文中还对间同1,2-聚丁二烯的链结构进行了分析。

Crystal structure of (5R,10R)-2,7-dibromo-3,8-dihydroxy-5,10-dimethoxy-5,10-dihydrochromeno[5,4,3-cde]chromene sesquihydrate, C16H12Br2O6 center dot 1.5H(2)O

C16H15Br2O7.5, orthorhombic, P2(1)2(1)2 (no. 18), a = 18.483(2) angstrom, b = 9.413(1) angstrom, c = 10.072(1) angstrom, V = 1752.3 angstrom(3), Z = 4, R-gt(F) = 0.083, wR(ref)(F-2) = 0.202, T= 293 K.

Hydrothermal synthesis and crystal structure of cluster compound {[Ni(enMe)(2)][SiW12O40]}[Ni(enMe)(2)(H2O)(2)](2) center dot 3H(2)O

the novel One-dimensional chain structure of the title cluster compound was synthesized and characterized by elemental analysis, IR spectra, TGA and X-ray single-crystal diffraction. The title cluster compound crystallized in a monochnic system with space group C2/c, a = 1.2656 nm, b = 2.20656 (4) nm, c =2.26763 (4) nm, beta = 92.078 degrees, V = 6.32852 (16) nm(3), Z = 4, D-c = 3.801 g/cm(3), A = 2.271 mm(-1), F(000) = 6512, R-1= 0.0549, wR(2) = 0.1087. The structure building block of the structure is the polyanion [SiW12O40](6-) with alpha-Keggin structure. The clusters were linked together with one-dimensional infinite chain through [ Ni ( enMe) (2)] (2+) cations. The [ Ni ( enMe) (2) ( H2O) (2)] (2+) cations and water molecules were filled in the structure. The cluster compound was expanded to three-dimensional framework by hydrogen bond interactions among molecules.

用改进的ART-2网络建立移动机器人环境模型的研究

本文应用自适应共振理论中ART-2神经网络进行移动机器人环境障碍模式识别。ART-2神经网络在处理单方向渐变的模式输入时具有模式漂移的特点，机器人在静态环境中运动依赖这种特点，但在动态环境中模式漂移的特点却会对机器人的安全造成威胁。为此，设计了一种改进的ART-2神经网络，使得移动机器人同时适应在静态和动态环境中安全运动。

950℃、1.0～3.5GPa下斜长角闪岩脱水熔融——压力和时间对结构的影响

利用YJ-3000t和JL-3600t多顶砧压力机,以哀牢山造山带南部红河县大白能—乐育剖面上的天然块状斜长角闪岩为初始样品,在950℃、1.0～3.5GPa、恒温20～300h条件下进行了两个系列的斜长角闪岩块状样品脱水部分熔融实验:(1)保持温度T=950℃,加热时间t=100h不变,改变压力(1.0～3.5GPa)的实验;(2)保持温度T=950℃,压力p=3.0GPa不变,改变加热时间(20～300h)的实验。结果表明,1.0～3.5GPa、950℃、恒温100h的条件下,随压力升高,斜长角闪岩中依次生成了单斜辉石+石榴石+熔体的矿物组合(1.0～1.5GPa)和单斜辉石+石榴石+熔体+硬玉+SiO2矿物+蓝晶石(2.0～3.5GPa)的矿物组合。3.0GPa、950℃条件下,随加热时间增加,实验产物中依次生成了单斜辉石+石榴石+熔体+硬玉+SiO2矿物+蓝晶石的矿物组合(20～100h)和单斜辉石+石榴石+熔体的矿物组合(150～300h)。斜长角闪岩的原岩结构决定了实验产物中新生矿物和熔体的分布。依据实验产物的矿物组合和新生矿物的分布特征,讨论了950℃、1.0～3.5GPa、恒温(20～300h)条件下,斜长角闪岩部分熔融过程的结构变化、变质反应以及石榴石冠状体的成因。

EDTA对狭叶香蒲吸收水中Cu^2＋及Cu^2＋在组织中迁移的影响

水培实验研究表明，100mg／L的Cu^2＋和0．5mmol／L的EDTA对狭叶香蒲（Typha angustifolia L．）的生长起到抑制作用。同时0．5mmol／L的EDTA能够促进狭叶香蒲吸收水中的Cu^2＋，并促进Cu^2＋从须根向地上部分转移，茎和叶中积累的Cu^2＋浓度为1233．8mg／kg和632．3mg／kgDW（干重），Cu^2＋从须根转移到茎部分的转移系教TFs从0．95上升到2．15；从须根转移到叶部分的转移系教从0．48上升到1．10.

Tryptophan degradation in irritable bowel syndrome: evidence of indoleamine 2,3-dioxygenase activation in a male cohort

Background: Irritable bowel syndrome (IBS) is a common disorder that affects 10–15% of the population. Although characterised by a lack of reliable biological markers, the disease state is increasingly viewed as a disorder of the brain-gut axis. In particular, accumulating evidence points to the involvement of both the central and peripheral serotonergic systems in disease symptomatology. Furthermore, altered tryptophan metabolism and indoleamine 2,3-dioxygenase (IDO) activity are hallmarks of many stress-related disorders. The kynurenine pathway of tryptophan degradation may serve to link these findings to the low level immune activation recently described in IBS. In this study, we investigated tryptophan degradation in a male IBS cohort (n = 10) and control subjects (n = 26). Methods: Plasma samples were obtained from patients and healthy controls. Tryptophan and its metabolites were measured by high performance liquid chromatography (HPLC) and neopterin, a sensitive marker of immune activation, was measured using a commercially available ELISA assay. Results: Both kynurenine levels and the kynurenine:tryptophan ratio were significantly increased in the IBS cohort compared with healthy controls. Neopterin was also increased in the IBS subjects and the concentration of the neuroprotective metabolite kynurenic acid was decreased, as was the kynurenic acid:kynurenine ratio. Conclusion: These findings suggest that the activity of IDO, the immunoresponsive enzyme which is responsible for the degradation of tryptophan along this pathway, is enhanced in IBS patients relative to controls. This study provides novel evidence for an immune-mediated degradation of tryptophan in a male IBS population and identifies the kynurenine pathway as a potential source of biomarkers in this debilitating condition.

Osteoclastogenesis induced by sRANKL and M-CSF from the non-adherent cell population of human bone marrow is inhibited by rhBMP-2 alone or together with rhVEGF

During bone development and repair, angiogenesis, osteogenesis and bone remodelling are closely associated processes that share some common mediators. In the present study non-adherent human bone marrow mononuclear cells under the induction of sRANKL and M-CSF, differentiated into osteoclasts with TRAP positive staining, VNR expression, and Ca-P resorptive activity. The effects of various combinations of rhBMP-2 (0, 3, 30, 300 ng/ml) and rhVEGF (0, 25 ng/ml) on osteoclastogenesis potentials were examined in this experimental system. The percentages of TRAP-positive multiple nucleated cells represent osteoclast differentiation potential and the percentages of resorptive areas in the Ca-P coated plates resemble osteoclast resorption capability. The presence of rhBMP-2 at 30 and 300 ng/ml showed inhibitory effects on osteoclast differentiation and their resorptive capability in the human osteoclast culture system. rhVEGF (25 ng/ml) enhanced the resorptive function of osteoclast whenever it was used alone or combined with 3 ng/ml rhBMP-2. However, rhVEGF induced resorptive function was inhibited by 30 ng/ml and 300 ng/ml rhBMP-2 at a dose-dependent manner. Statistical analysis demonstrated that an interactive effect exists between rhBMP-2 and rhVEGF on human osteoclastogenesis. These findings suggested that an interactive regulation may exist between BMPs and VEGF signaling pathways during osteoclastogenesis, exact mechanisms are yet to be elucidated.

Increased concentrations of the oxidative DNA adduct 7, 8-dihydro-8-oxo-2-deoxyguanosine in the germ-line of men with type 1 diabetes

The effects of diabetes mellitus on male reproductive health have not been clearly defined. A previous publication from this group reported significantly higher levels of nuclear DNA fragmentation and mitochondrial DNA deletions in spermatozoa from men with type 1 diabetes. This study compared semen profiles, sperm DNA fragmentation and levels of oxidative DNA modification in spermatozoa of diabetic and non-diabetic men. Semen samples from 12 non-diabetic, fertile men and 11 type 1 diabetics were obtained and subjected to conventional light microscopic semen analysis. Nuclear DNA fragmentation was assessed using an alkaline Comet assay and concentrations of 7,8-dihydro-8-oxo-2-deoxyguanosine (8-OHdG), an oxidative adduct of the purine guanosine, were assessed by high-performance liquid chromatography. Conventional semen profiles were similar in both groups, whilst spermatozoa from type 1 diabetics showed significantly higher levels of DNA fragmentation (44% versus 27%; P < 0.05) and concentrations of 8-OHdG (3.6 versus 2.0 molecules of 8-OHdG per 105 molecules of deoxyguanosine; P < 0.05). Furthermore, a positive correlation was observed between DNA fragmentation and concentrations of 8-OHdG per 105 molecules of deoxyguanosine (rs = 0.7, P < 0.05). The genomic damage evident in spermatozoa of type 1 diabetics may have important implications for their fertility and the outcome of pregnancies fathered by these individuals.

Electrochemical oxidation of nitrite and the oxidation and reduction of NO2 in the room temperature ionic liquid [C(2)mim][NTf2]

The electrochemical oxidation of potassium nitrite has been studied in the room temperature ionic liquid (RTIL) [C(2)mim][NTf2] by cyclic voltammetry at platinum electrodes. A chemically irreversible oxidation peak was observed, and a solubility of 7.5(+/- 0.5) mM and diffusion coefficient of 2.0(+/- 0.2) x 10(-11) m(2) s(-1) were calculated from potential step chronoamperometry on the microdisk electrode. A second, and sometimes third, oxidation peak was also observed when the anodic limit was extended, and these were provisionally assigned to the oxidation of nitrogen dioxide (NO2) and nitrate (NO3-), respectively. The electrochemical oxidation of nitrogen dioxide gas (NO2) was also studied by cyclic voltammetry in [C(2)mim][NTf2] on Pt electrodes of various size, giving a solubility of ca. 51(+/- 0.2) mM and diffusion coefficient of 1.6(+/- 0.05) x 10(-10) m(2) s(-1) (at 25 degrees C). It is likely that NO2 exists predominantly as its dimer, N2O4, at room temperature. The oxidation mechanism follows a CE process, which involves the initial dissociation of the dimer to the monomer, followed by a one-electron oxidation. A second, larger oxidation peak was observed at more positive potentials and is thought to be the direct oxidation of N2O4. In addition to understanding the mechanisms of NO2- and NO2 oxidations, this work has implications in the electrochemical detection of nitrite ions and of NO2 gas in RTIL media, the latter which may be of particular use in gas sensing.

The electrochemical oxidation and reduction of nitrate ions in the room temperature ionic liquid [C(2)mim][NTf2]; the latter behaves as a 'melt' rather than an 'organic solvent'

The electrochemical oxidation of 1-butyl-3-methylimidazolium nitrate [C(4)mim][NO3] was studied by cyclic voltammetry in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [C(2)mim][NTf2]. A sharp peak was observed on a Pt microelectrode (d = 10 mu m), and a diffusion coefficient at infinite dilution of ca. 2.0 x 10(-11) m(2) s(-1) was obtained. Next, the cyclic voltammetry of sodium nitrate (NaNO3) and potassium nitrate (KNO3) was studied, by dissolving small amounts of solid into the RTIL [ C2mim][ NTf2]. Similar oxidation peaks were observed, revealing diffusion coefficients of ca. 8.8 and 9.0 x 10(-12) m(2) s(-1) and solubilities of 11.9 and 10.8 mM for NaNO3 and KNO3, respectively. The smaller diffusion coefficients for NaNO3 and KNO3 (compared to [C(4)mim][NO3]) may indicate that NO3- is ion-paired with Na+ or K+. This work may have applications in the electroanalytical determination of nitrate in RTIL solutions. Furthermore, a reduction feature was observed for both NaNO3 and KNO3, with additional anodic peaks indicating the formation of oxides, peroxides, superoxides and nitrites. This behaviour is surprisingly similar to that obtained from melts of NaNO3 and KNO3 at high temperatures ( ca. 350 - 500 degrees C), and this observation could significantly simplify experimental conditions required to investigate these compounds. We then used X-ray photoelectron spectroscopy (XPS) to suggest that disodium( I) oxide (Na2O), which has found use as a storage compound for hydrogen, was deposited on a Pt electrode surface following the reduction of NaNO3.

SO2 Saturation of the Room Temperature Ionic Liquid [C(2)mim][NTf2] Much Reduces the Activation Energy for Diffusion

The physical effect of high concentrations of reversibly dissolved SO2 on [C(2)mim][NTf2] was examined using cyclic voltammetry, chronoamperometry, and ESR spectroscopy. Cyclic voltammetry of the oxidation of solutions of ferrocene, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), and chloride in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesufonyl)imide ([C(2)mim][NTf2]) reveals an increase in limiting current of each species corresponding to the addition of increasing concentrations of sulfur dioxide. Quantitative chronoamperometry reveals an increase in each species' diffusion coefficient with SO2 concentration. When chronoamperometric data were obtained for ferrocene in [C(2)mim][NTf2] at a range of temperatures, the translational diffusion activation energy (29.0 +/- 0.5 kJ mol(-1)) was found to be in good agreement with previous studies. Adding SO2 results in apparent near-activationless translational diffusion. A significant decrease in the activation energy of rotational diffusion with the SO2 saturation of a 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) solution in [C(2)mim][NTf2] (29.9 +/- 2.0 to 7.7 +/- 5.3 kJ mol(-1)) was observed using electron spin resonance (ESR) spectroscopy. The reversible physical absorption Of SO2 by [C(2)mim][NTf2] should have no adverse effect on the ability of that ionic liquid to be employed as a solvent in an electrochemical gas sensor, and it is possible that the SO2-mediated reduction of RTIL viscosity could have intrinsic utility.

Crystal structure of pyridinium 1,1 '-bis(4-hydroxy-pyrimid-6-on-2-thion-5-yl)-1 ''-(4-nitrophenyl)methane methanol solvate monohydrate, (C5H6N)(C15H10N5O6S2)center dot CH3OH center dot H2O

C21H22N6O8S2, monoclinic, P12(1)/n1 (no. 14), a = 10.1931(8) angstrom, b = 11.9627(7) angstrom, c = 20.299(2) angstrom, beta = 95.131(4)degrees, V = 2465.2 A(3), Z = 4, R-gt(F) = 0.079, wR(ref)(F-2) = 0.229, T = 100 K.