Enhancement of uranium(VI) biomineralization by Saccharomyces cerevisiae through addition of inorganic phosphorus

Journal of Radioanalytical and Nuclear Chemistry - Enhancement of U(VI) biomineralization by Saccharomyces cerevisiae through addition of inorganic phosphorus was studied in this work. The addition...     

Serum pharmacochemistry combined with multiple data processing approach to screen the bioactive components and their metabolites in Mutan Cortex by ultra‐performance liquid chromatography tandem mass spectrometry

Root cortex of Paeonia suffruticosa Andrews (Paeoniaceae), known as Moutan Cortex (MC), is known to have anti‐allergic and anti‐inflammatory properties. However, the constituents absorbed into blood after oral administration of MC remain unknown. A sensitive and rapid method by ultra‐high‐pressure liquid chromatography–electrospray ionization–quadrupole‐time‐of‐flight mass spectrometry (UPLC‐ESI‐Q‐TOF‐MS) technology and the MetaboLynx^TM software combined with multiple data processing approach (Mdpa) was established to investigate the absorbed constituents in rats after oral administration of MC, providing unique high‐throughput capabilities for drug metabolism study. A hyphenated electrospray ionization and quadrupole‐time‐of‐flight analyzer was used for the determination of accurate mass of the fragment ion in negative mode, with excellent MS mass accuracy and enhanced data acquisition. This rapid automated analysis method was successfully applied for screening and identification of the constituents absorbed and metabolized studies of MC after oral administration to rats. A total of 46 peaks were obtained from MC, 41 of which were tentatively characterized. In the VIP‐plot of orthogonal partial least‐squares discriminant analysis, 23 interesting ions in serum samples were extracted, and 16 parent components and seven metabolites were detected in vivo. The integrative serum pharmacochemistry technique, UPLC‐ESI‐Q‐TOF‐MS, and Mdpa method were successfully applied for rapid discovery of multiple components from MC. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of aryl-functionalized, 1,5-disubstituted 1,2,3-triazoles and derivatives by arylation of zwitterionic ruthenium triazolato complexes

The synthesis of a series of ruthenium 1,5-disubstituted 1,2,3-triazolato complexes, 1,5-disubstituted 1,2,3-triazoles, and a triazolium salt is reported. Treatment of the ruthenium azido complex [Ru]-N₃ ( 1 , [Ru] = (η⁵-C₅H₅)(dppe)Ru, dppe = Ph₂PCH₂CH₂PPh₂) with an excess of ethyl propiolate results in the formation of a mixture of the Z- and E-forms of zwitterionic N(1)-bound N(3)-ethyl acryl-4-carboxylate triazolato complexes [Ru]N₃(CH=CHCO₂Et)C₂H(CO₂) ( Z - 2 ) and ( E - 2 ). The arylation of 2 with aromatic bromides gives a series of cationic N(1)-bound N(3)-ethyl acryl-4-alkoxycarbonyl triazolato complexes {[Ru]N₃(CH=CHCO₂Et)C₂H(CO₂CH₂R)}[Br] ( 3a , R = Ph ; 3b , R = C₆F₅; 3c , R = 4-C₆H₄CN, 3d , R = 2,6-C₆H₃F₂) and the subsequent cleavage of the Ru-N bond of 3a–d gives 1,5-disubstituted 1,2,3-triazoles N₃(CH=CHCO₂Et)C₂H(CO₂CH₂R) ( 4a , R = Ph; 4b , R = C₆F₅; 4c , R = 4-C₆H₄CN; 4d , R = 2,6-C₆H₃F₂) and [Ru]-Br. A 1,2,3-triazolium salt [N₃(CH=CHCO₂Et)(CH₂C₆F₅)C₂H₂][Br] ( 5 ) was formed by transformation of 4b in BrCH₂C₆F₅/chloroform mixture. The structures of Z-3a and Z-5 were confirmed by single-crystal x-ray diffraction analysis and both complexes participate in non-covalent aromatic interactions in the solid-state structures which can be favorable in the binding of DNA/biomolecular targets and have shown great potential in the application of biologically active anticancer drugs.     

Structure determination and magnetic studies of triazole chelated Co(II) coordination polymers

Two cobalt(II) halide complexes with 1,2,4-triazole as a ligand were synthesized. Their structures were determined by extended x-ray absorption fine structure (EXAFS) and powder x-ray diffraction (XRD). Both complexes [Co(Htrz)Cl₂]_n ( 1 ) and {[Co(Htrz)₂(trz)]BF₄}_n ( 2 ) form one-dimensional polymeric chain and the distances of Co⋯Co are 3.3521(2) Å and 3.8629(2) Å, respectively. The Htrz and Cl⁻ are bridging ligands to connect two Co(II) ions in 1 , and the local environment of Co site is in a distorted octahedron with {CoN₂Cl₄} core. In complex 2 , two Htrz and one trz are bridging ligands to connect two Co(II) ions, and the local geometry of Co is in a pseudo octahedron with {CoN₆} core. The analysis of Co L_II,III-edge XAS indicates that the Co(II) of both complexes are at high spin state with t_2g⁵e_g² configuration and the crystal field strength (10Dq) is about 1.2 eV. The broken-symmetry DFT calculations indicate that antiferromagnetic coupling state of Co⋯Co is the most stable state in both complexes; and the coupling constants of 1 and 2 are −0.32 cm⁻¹ and −3.70 cm⁻¹, respectively. Based on the distances of Co⋯Co and coupling constants, such antiferromagnetic interaction is achieved through triazole ligands.     

High-pressure infrared spectroscopy of ionic liquids mixed with Tween 80

In this study, the possibility of using Tween 80 to disturb the microstructures of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF₆) was investigated under high pressures. The imidazolioum C H absorptions of pure ionic liquids (ILs) are significantly blue-shifted under high pressures. However, mild changes in imidazolioum C H stretching frequencies were observed for IL/Tween 80 mixtures. Tween 80 may hinder cations of ILs to form network structures with anions under high pressures via pressure-enhanced cation-Tween 80 interactions. Based on the experimental results, Tween 80-[BMIM]PF₆ interactions are more effective in disturbing the local structure of imidazolium C H than Tween 80-[BMIM]BF₄ interactions.     

Silver/graphene–polypyrrole composite for levosimendan detection

This study used a facile method to develop a novel silver/Graphene–polypyrrole (Ag/G–PPy)-modified electrode that can be used as an electrochemical sensor for levosimendan detection. The properties of the synthesized Ag/G–PPy-modified electrode were examined through field-emission scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. The Ag/G–PPy-modified electrode exhibited satisfactory current signals toward levosimendan concentrations ranging from 0.21 to 6.88 μM and exhibited a low detection limit (0.12 μM). Accordingly, the proposed electrode can serve as a simple and inexpensive electrochemical sensor for levosimendan detection.     

厌氧消化过程化学变化的教学研究

有氧和无氧分解是生物体代谢有机物的2种途径,前者一直是生物化学课程中物质代谢的教学核心和重点。厌氧消化是有机物经无氧分解生成甲烷和二氧化碳的途径,相比于有氧分解,其具有化学反应众多、中间产物多、途径复杂等特点,同时对维护自然生态平衡、物质循环和人类社会的绿色健康发展等具有重要作用。如此重要的途径长期以来一直没有在生物化学教材与教学内容中体现,亟需进行教学改革。利用布鲁姆教学目标分类理论将厌氧消化过程中的主要反应、氧化还原过程及电子传递、热力学变化及串联反应等知识进行系统介绍,对物质代谢的另一条无氧路径进行补充,丰富了学生代谢网络的知识框架,完善了生物化学教学体系,相关教学内容和经验可供同行参考借鉴,对相关课程教学改革具有重要价值。     

Rich-defect carbon nanotubes for highly sensitive detection of Dopamine

Dopamine (DA) plays an essential role in the central nervous, renal, hormonal and cardiovascular systems. Various modified carbon nanotubes (CNT)-based dopamine sensors have been reported, but inexpensive, highly sensitive plain CNT-based ones are seldom studied. In this work, a facile and inexpensive CNT-based DA sensor is made by rich-defect multi-walled carbon nanotubes (RD-CNT) via an ultrasound method. The defect and elemental states of the RD-CNT are systematically studied by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray powder diffraction (XRD) and X-ray-photoelectron spectroscopy (XPS). Results show that massive holes and cracks exist in RD-CNT. The level of defects increases from the additional exposed edges. The electrochemical characterizations indicate that the electrochemical sensor has the highest sensitivity of 438.4 μA/(μM ⋅ cm²) among all carbon materials-based DA sensors while well meeting the clinically required detection range and selectivity. The DA sensor was further used to detect live healthy human serum and live PC12 cells with satisfactory results, thus holding great promise for an inexpensive but sensitive DA sensor in practical applications of clinical diagnosis and biological research.     

Amperometric sandwich-type aptasensor based on peroxidase mimetic Au@Pt for the carcinoembryonic antigen

For sensitive analysis of cancer biomarker carcinoembryonic antigen (CEA), an amperometric sandwich-type aptasensor is proposed based on a signal amplification strategy of Au@Pt bimetallic nanoprobes. As the excellent catalytic activity to hydrogen peroxide (H₂O₂), core-shell Au@Pt nanoparticles are employed as nanoprobes by conjugating directly with the secondary aptamer of CEA (Apt-II). Due to the synergic recognition effect of dual aptamers and the excellent catalytic activity of nanoprobes, this amperometric sandwich-type aptasensor for CEA exhibits high specificity and good sensitivity with a limit of detection of 0.31 ng/mL, along with a wide linear range from 0.1 ng/mL to 100 ng/mL.