反相高效液相色谱法分离测定复合维生素片剂中VB1,VB2,VB6和烟酰胺

采用NovaPak C18色谱柱(30 cm×3.9 mm,粒径10 μm),以(V(水)V(甲醇)V(冰乙酸)m(庚烷磺酸钠)=730 mL270 mL5 mL400 mg)为流动相,检测波长为280 nm,分离测定了复合维生素片剂中的VB1,VB2,VB6和烟酰胺,实验回收率分别为100.5%,96.8%,98.1%,102.0%,相对标准偏差RSD分别为0.8%,0.4%,0.5%,1.2%(n=5),检出限分别为39,4.2,4.7,10 ng.本法已用于复合维生素片剂中VB1,VB2,VB6和烟酰胺的分离和测定.     

ChemInform Abstract: Synthesis and Crystal Structure of the A6B5O18 Perovskite-Like Compounds.

Single phase Ba₅KNb₅O₁₈ (I) is prepared by solid state reaction of Ba₅Nb₄O₁₅ and KNbO₃ (1370 K, 2 h), while Sr₆Nb₄SnO₁₈ (II) results from calcination of the coprecipitated metal hydroxycarbonates (1570 K, 2 h).     

ChemInform Abstract: Planarization of B7‐ and B12‐ Clusters by Isoelectronic Substitution: AlB6‐ and AlB11‐.

The structures and chemical bonding of AlB₆^‐ and AlB₁₁^‐ clusters are characterized by PES and DFT calculations.     

Anti-Inflammatory Effects of 6-Methylcoumarin in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and NF-κB Signaling Pathways

Persistent inflammatory reactions promote mucosal damage and cause dysfunction, such as pain, swelling, seizures, and fever. Therefore, in this study, in order to explore the anti-inflammatory effect of 6-methylcoumarin (6-MC) and suggest its availability, macrophages were stimulated with lipopolysaccharide (LPS) to conduct an in vitro experiment. The effects of 6-MC on the production and levels of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α) and inflammatory mediators (nitric oxide (NO), prostaglandin E₂ (PGE₂)) in LPS-stimulated RAW 264.7 cells were examined. The results showed that 6-MC reduced the levels of NO and PGE₂ without being cytotoxic. In addition, it was demonstrated that the increase in the expression of pro-inflammatory cytokines caused by LPS stimulation, was decreased in a concentration-dependent manner with 6-MC treatment. Moreover, Western blot results showed that the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which increased with LPS treatment, were decreased by 6-MC treatment. Mechanistic studies revealed that 6-MC reduced the phosphorylation of the mitogen-activated protein kinase (MAPK) family and IκBα in the MAPK and nuclear factor-kappa B (NF-κB) pathways, respectively. These results suggest that 6-MC is a potential therapeutic agent for inflammatory diseases that inhibits inflammation via the MAPK and NF-κB pathways.     

ChemInform Abstract: Theoretical and Experimental Investigations on the Protonation of Substituted closo-Hexaborates — [B6H5HfacF]- and [B6H5HfacCH3]-.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Gas‐Phase Stability of Derivatives of the closo‐Hexaborate Dianion B6H2‐6.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Molecular and Electronic Structures of TiMH+6 (M: B,Al, Ga) Compounds.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Structure and stability of B6, B,and B clusters

We investigated various isomers of B₆, B, and B clusters with ab initio [Hartree–Fock (HF), MP2)] and density functional theory (DFT) methods. Ten B₆ isomers, 6 B isomers, and 6 B isomers are determined to be local minima on their potential energy hypersurfaces by the HF, B3LYP, B3PW91, and MP2 methods. Fourteen of these structures are first reported. The most stable neutral B₆ cluster is the capped pentagonal pyramid (C_5v), in agreement with the results reported previously. Hexagon B (C_2h) isomer and fan‐shaped B (C_2v) isomer are found to be the most stable on the cationic and anionic energy hypersurfaces, respectively. Natural bond orbital analysis suggests that there are three‐centered bonds in the most stable B₆ neutral and ionic clusters. The multicentered bonds are responsible for the special stability of the lowest‐energy isomer. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 269–278, 2003     

ChemInform Abstract: B4H2- 6: New Low Symmetry Structures for Triborylborane Dianion.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Structure and Aromaticity of B6H5+ Cation: A Novel Borhydride System Containing Planar Pentacoordinated Boron

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Substitution of Fe and B for Al in the Pollucite (CsAlSi2O6) Structure.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Crystal Structure of Cs2[B6H5(SCN)].

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: The Known and Unknown Group 13 Hydride Molecules M2H6: Diborane(6), Dialane(6), and Digallane(6).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.