A combined diffraction and dielectric properties investigation of Ba3MnNb2O9 complex perovskites

A combined synthesis, diffraction and dielectric properties investigation of the dependence (and effect) of Mn²⁺/Nb⁵⁺ ordering in Ba₃MnNb₂O₉ (BMN) upon annealing atmosphere and processing conditions has been carried out. Annealing in different atmospheres was not found to significantly alter either nominal stoichiometry or structure type. The obtained structure type (disordered metrically cubic or ordered trigonal) as well as the measured electrical properties (in particular, the dielectric loss) were, however, found to be sensitive to the synthesis route. Samples obtained via solid-state reaction were found to be predominantly of 1:2 Mn²⁺/Nb⁵⁺ ordered, trigonal structure type whereas samples obtained via an aqueous solution route were found to be of a Mn²⁺/Nb⁵⁺ ‘disordered’, metrically cubic structure type. All solid-state synthesized samples showed reasonable dielectric properties. The microwave dielectric constant and dielectric quality factor, Q, at 8 GHz of an as-synthesized BMN sample were 38 and 100, respectively. By contrast, the dielectric loss of the metrically cubic, Mn²⁺/Nb⁵⁺ ‘disordered’ samples obtained via an aqueous solution synthesis process were significantly worse.     

A non-catalytic approach to the synthesis of 5,6-dihydrobenzo[h]quinolines

A concise synthesis of highly functionalized 5,6-dihydrobenzo[h]quinoline-3-carbonitriles is delineated through base induced ring transformation of 4-sec-amino-2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles with S-methylisothiourea sulfate and 1-carboxamidinepyrazole hydrochloride, separately, in DMF. Under analogous reaction conditions the ring transformation of 4-sec-amino-2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles by formamidine acetate provided 4-sec-amino-benzo[h]quinoline-3-carbonitriles in moderate yields, while with benzamidine hydrochloride, the reaction followed the same mechanism to yield 2-phenyl-4-sec-amino-5,6-dihydrobenzo[h]quinoline-3-carbonitriles.     

An unusual synthesis of tetrahydrobenzo[f]isoquinolines

A facile and short synthesis of 2-oxo-4-sec-amino-2,3,5,6-tetrahydrobenzo[f]isoquinoline-1-carbonitriles has been delineated through base catalyzed ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by cyanoacetamide in excellent yields.     

手性叠氮呋喃酮及其三唑类化合物的合成

合成了手性叠氮2(5H)-呋喃酮化合物(3a～3d);3b与含活泼亚甲基化合物发生偶极环加成反应,合成了带手性丁烯内酯的1,2,3-三唑化合物(8b和8b)。3,7和8的结构经1HNMR,13CNMR,IR和HR-MS表征。探讨了合成反应的机理。     

FTIR and WAXS analysis of periodate oxycellulose: Evidence for a cluster mechanism of oxidation

Cellulose paper (Whatman no.1, chromatographic grade) was oxidised with 0.1 M sodium metaperiodate at different oxidation levels (0–11 days at room temperature), and analysed with FTIR before and after chemical treatments (reduction, further oxidation, alkaline hydrolysis). The deconvolution of infrared data allowed us to verify that periodate oxidises cellulose in isolated domains, leading to the decrease of crystallinity, in agreement with the results of wide angle X-ray scattering (WAXS). In particular, the alkaline hydrolysis (β-alkoxy fragmentation) followed by mild acid treatment removed the oxidised groups and recovered most of the crystallinity of cellulose, as determined by the FTIR crystallinity index.     

LiNi0.8Co0.2O2 / MWNTs复合物超级电容器电极材料的研究

Multiwalled carbon nanotubes (MWNTs) were used as the conductive additive in the electrode materials. The electrochemical properties of supercapacitors based on LiNi_0.8Co_0.2O₂ / MWNTs composite and LiNi_0.8Co_0.2O₂/acetylene black composite and MWNTs in 1.0 mol·L^-1 LiClO₄ / EC+DEC [V(EC)∶V(DEC)=1∶1] electrolyte were investigated by means of constant charge/discharge current tests, respectively. The experimental results show that the LiNi_0.8Co_0.2O₂ / MWNTs composite has better performance than that of others, and the maximum specific capacitance of the supercapacitor can reach 271.6 F·g^-1, while the energy density is up to 339.5 Wh·kg^-1. Furthermore, it is remarkable that the performance of MWNTs is better than that of acetylene black as the conductive additive.     

离子液体介质中FeCl3•6H2O催化下芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应

考察了在离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim][BF₄])介质中, 芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应. 实验结果表明, 在催化量的FeCl₃•6H₂O存在下, 该反应可高产率地生成氧杂蒽二酮类化合物3; 而在TMSCl/FeCl₃•6H₂O复合催化体系的催化下, 则得到氧杂蒽二酮类化合物的开环衍生物4, 反应具有非常好的选择性. 该论文提供的方法操作简单、产率高、选择性好而且对环境友好. 在反应结束后, 所用催化剂及离子液体都很容易回收, 并能有效重复使用.     

Effects of pH and Dye Concentration on the Optical and Structural Properties of Coumarin-4 Dye-Doped SiO2-PDMS Xerogels

Optical and structural properties of coumarin-4 dye-doped SiO₂-PDMS xerogels synthesized by acid catalyzed (one-step) and acid-base catalyzed (two-step) sol-gel routes with varying pH (0.6 to 7) and dye content ( 5 × 10^–4 to 5 × 10^–2 mole) are reported. Spectroscopic methods such as photo-luminescence, FT-IR and FT-Raman were used for characterizations. The acid catalyzed xerogels prepared with pH < 2.5 exhibited two fluorescence peaks, I at 390 nm and II at 480 nm. The acid-base catalyzed xerogels synthesized with pH < 2.5 also exhibited two peaks, I at 400 nm and II at 475 nm. Peak II was not observed for the samples with pH 2.5. This phenomenon was attributed to the existence of pH dependent different forms of coumarin-4 molecule. The concentration-quenching phenomenon was observed for the acid catalyzed xerogels prepared with different dye concentration. TheFT-IR spectra indicated the existence of hydrogen bonds between the carbonyl groups of dye molecules and the silanol groups of gel matrix. The hydrogen bonding was the highest for the samples with the extremity pH, 0.6 and 7, resulting in the highest dye/gel matrix interactions, hence, the highest fluorescence peaks. The Raman studies indicated that the samples prepared with pH < 2.5 possessed relatively more number of 3-membered siloxane rings than 4-membered siloxane rings. The ring statistics was reversed for the samples with pH > 2.5. The number of silanol groups was higher for the samples with pH > 2.5.     

2-Deoxy-d-glucose Promotes Buforin IIb-Induced Cytotoxicity in Prostate Cancer DU145 Cells and Xenograft Tumors

Inhibition of the glycolytic pathway is a critical strategy in anticancer therapy because of the role of aerobic glycolysis in cancer cells. The glycolytic inhibitor 2-Deoxy-d-glucose (2-DG) has shown potential in combination with other anticancer agents. Buforin IIb is an effective antimicrobial peptide (AMP) with broad-spectrum anticancer activity and selectivity. The efficacy of combination treatment with 2-DG and buforin IIb in prostate cancer remains unknown. Here, we tested the efficacy of buforin IIb as a mitochondria-targeting AMP in the androgen-independent human prostate cancer cell line DU145. Combining 2-DG with buforin IIb had a synergistic toxic effect on DU145 cells and mouse xenograft tumors. Combination treatment with 2-DG and buforin IIb caused stronger proliferation inhibition, greater G1 cell cycle arrest, and higher apoptosis than either treatment alone. Combination treatment dramatically decreased L-lactate production and intracellular ATP levels, indicating severe inhibition of glycolysis and ATP production. Flow cytometry and confocal laser scanning microscopy results indicate that 2-DG may increase buforin IIb uptake by DU145 cells, thereby increasing the mitochondria-targeting capacity of buforin IIb. This may partly explain the effect of combination treatment on enhancing buforin IIb-induced apoptosis. Consistently, 2-DG increased mitochondrial dysfunction and upregulated Bax/Bcl-2, promoting cytochrome c release to initiate procaspase 3 cleavage induced by buforin IIb. These results suggest that 2-DG sensitizes prostate cancer DU145 cells to buforin IIb. Moreover, combination treatment caused minimal hemolysis and cytotoxicity to normal WPMY-1 cells. Collectively, the current study demonstrates that dual targeting of glycolysis and mitochondria by 2-DG and buforin IIb may be an effective anticancer strategy for the treatment of some advanced prostate cancer.     

Novel 1,3,5-thiadiazine-2-thione derivatives containing a hydrazide moiety: Design,synthesis and bioactive evaluation against phytopathogenic fungi in vitro and in vivo

A series of novel 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety were designed, synthesized and evaluated for their biological activities against phytopathogenic fungi. The antifungal bioassays indicated that the title compound 5b impressively displayed the obvious selectivity and specificity aganist Rhizoctonia solani (Rs) in vitro and in vivo. The above researches provide a significant reference for the further structural optimization of 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety as potential fungicides.