Three new secoiridoid glycosides from the rhizomes and roots of Gentiana scabra and their anti-inflammatory activities

Three new (1–3) and 17 known (4–20) iridoid and secoiridoid glycosides were isolated from a methanol extract of the rhizomes and roots of Gentiana scabra. Their chemical structures were elucidated from 1D and 2D NMR, IR absorption, and HR-ESI-MS spectra, as well as comparisons of these data with reported values. The effects of the isolated compounds on lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells were investigated. Compounds 6, 10 and 20 exhibited significant inhibitory effects on LPS-induced IL-12 p40 and IL-6 production with IC₅₀ values of 1.62–14.29 μM. Compound 10 also showed a strong inhibitory effect on the LPS-stimulated production of TNF-α with an IC₅₀ value of 10.45 μM.     

基于CdTe量子点荧光猝灭-恢复方法测定磷酸根

水相合成了巯基乙酸保护的Cd Te量子点。根据Fe3+存在的情况下,Cd Te量子点荧光强度恢复程度与磷酸根浓度成正比的现象,建立了基于Cd Te量子点荧光淬灭-恢复测定磷酸根的方法。考察了溶液p H值以及Fe3+浓度对检测体系的影响。在p H=7.1,Fe3+为4.0μmol·L-1条件下,磷酸根浓度在4.0×10-6~1.0×10-4mol·L-1范围内,与量子点荧光恢复程度呈良好的线性关系,检出限为8.0×10-7mol·L-1。本方法可用于实际样品中磷酸根的检测,回收率为95.4%~108.6%。     

Non-resonant and resonant x-ray scattering studies on multiferroic TbMn2O5

Comprehensive x-ray scattering studies, including resonant scattering at Mn L, Tb L, and M edges, were performed on single crystals of TbMn2O5 for crystallographic data to elucidate the nature of its commensurate and incommensurate phases. The scattering results provide direct evidence of symmetry lowering to the ferroelectric phase driven by magnetically induced lattice modulations and show the presence of multiple magnetic orders. The competing orders under spin-frustrated geometry are believed to cause discommensuration and result in the commensurate-to-incommensurate phase transition around 24 K. It is proposed that the low temperature incommensurate phase consists of commensurate domains separated by antiphase domain walls which change both signs of spontaneous polarizations and x-ray scattering amplitudes for forbidden reflections.     

Synthesis and spectroscopic studies of cyclometalated Pt(II) complexes containing a functionalized cyclometalating ligand, 2-phenyl-6-(1H-pyrazol-3-yl)-pyridine

Three new luminescent cyclometalated Pt(II) complexes, [Pt(L)Cl] (1), [Pt2(L-)2] (2), and [Pt(L)(PPh3)]ClO4 (3.ClO4) (where HL=2-phenyl-6-(1H-pyrazol-3-yl)-pyridine), were synthesized and characterized by X-ray crystallography. HL represents a new class of C,N,Npyrazolyl cyclometalating ligands containing a Cphenyl, a Npyridyl, and a Npyrazolyl donor moiety, as well as a 1-pyrazolyl-NH, that can also be available for metal coordination and other chemical interactions. Complex 1 possesses intense intraligand transitions at 275-375 nm and moderately intense metal-to-ligand charge transfer (1MLCT) (dpi(Pt)-->pi*(L)) transition at 380-410 nm. The room temperature solid-state emission lambdamax of 1 occurs at 580 nm and is attributable to the 3MMLCT (dsigma*(Pt)-->pi*(L)) transition. It also displays strong phosphorescence in acetonitrile solutions at room temperature with an emission lambdamax at 514 nm, which can be tentatively assigned to the 3MLCT (pi*(L)-->dpi(Pt)) transition. Complex 1 can be deprotonated in organic solvents to yield a cycloplatinated dimer 2, which shows a relatively high room-temperature luminescent quantum yield of 0.59 in DMF (lambdamax=509 nm). Substitution of the ancillary chloro-ligand in 1 by triphenylphosphine yields 3, which also possesses a good room-temperature luminescent quantum yield of 0.52 in DMF (lambdamax=504 nm) and a better solubility in water. Complex 3 is synthesized to demonstrate the pH dependence of luminescent properties of this C,N,Npyrazolyl cyclometalated Pt(II) system. Such a pH response is ascribable to the protonation/deprotonation of the 1-pyrazolyl-NH on the C,N,Npyrazolyl cyclometalating ligand. The pKa of the 1-pyrazolyl-NH in 3, measured in 1:2 (v/v) aqueous DMF solutions, is approximately 4.0.     

Effect of extracts from safflower seeds on osteoblast differentiation and intracellular calcium ion concentration in MC3T3-E1 cells

Although safflower seeds have long been used in Korea as herbal medicines, very little research has been published on the effects of safflower seed on bone formation or bone density. The study reported here therefore examined bone nodule formation, calcium uptake, alkaline phosphatase activity, and intracellular concentration of calcium ion [Ca(2+)](i) in murine osteoblastic cells of the MC3T3-E1 line that were cultured on modified Eagle's minimal essential medium alone (controls) or with addition of 0.1% crude extract of safflower seed (experimental group I) or 0.1% aqueous fraction of safflower seed (experimental group II). Fluorescence spectrometry measurement of ([Ca(2+)](i)) showed significantly accelerated rates of osteoblast differentiation in experimental group I (3 microL of crude extract in 8 x 10(4) cells) and experimental group II (2 microL of aqueous fraction in 8 x 10(4) cells) compared to the control group.     

基于H．264的RCPC信道编码非平等误码保护

为了提高压缩码流在无线信道中传输的可靠性,设计了基于RCPC(Rate Compatible Punctured Convolutional)信道编码的非平等误码保护方案,在保证编码效率的前提下,使视频信息在无线信道传输过程中具有更强的抗差错能力.实验结果证明,不等差错保护机制的运用有效地改善了视频在无线信道系统中的传输性能,保证了视频图像序列的可靠传输,而引入自适应不等差错保护则能更有效地利用信道的容量,提高了传输效率.     

干工况风机盘管-半集中式蒸发冷却空调系统

将集中式蒸发冷却空调和风机盘管结合在一起,形成干工况风机盘管-半集中式蒸发冷却空调系统,分析了该空调系统的理论基础,指出温湿度独立控制原理和DOAS的关系.讨论了干工况风机盘管的几种型式,归纳得出了简单的冷量分配计算公式,并在此基础上首次提出了新风比较系数的概念,以期达到简化设计的目的.     

Transition‐metal compatibilization of poly(4‐bromostyrene) and polybutadiene via palladium(0) catalyzed reactions

Immiscible blends of 1,2‐polybutadiene and poly(4‐bromostyrene) can be compatibilized by rather low concentrations of Pd⁽⁰⁾[P(C₆H₅)₃]₄ at ambient temperature and 60 °C under argon. Two distinct glass‐transition temperatures merge into a single glass‐transition temperature at high enough concentrations of Pd⁽⁰⁾ (i.e., 2 or 3 mol %). Compatibilization does not occur if Pd⁽⁰⁾ is absent, triphenylphosphine is added without Pd⁽⁰⁾, or polystyrene is not functionalized. The methodology described herein is also useful for inducing melting‐point depression of 2,7‐dibromofluorene in ternary complexes with 1,2‐polybutadiene and Pd⁽⁰⁾. A 72/28 complex of poly(4‐bromostyrene) and 1,2‐polybutadiene with 5.5 mol % Pd⁽⁰⁾ exhibits a reinforced rubbery response with a modulus of 1.2 × 10⁷ N/m², a fracture strain of 235%, and a single glass‐transition temperature. Mechanical properties of these compatibilized ternary systems compare well with those of styrene–butadiene block copolymers, particularly above 100% strain. A five‐step mechanism that includes oxidative addition, olefin coordination, migratory insertion, β‐hydride elimination, and reductive elimination in the coordination sphere of the transition metal is proposed to illustrate how either poly(4‐bromostyrene) or 2,7‐dibromofluorene is linked covalently to alkene side groups in the diene polymer via the Heck reaction. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 677–688, 2001     

Fourier transform ion cyclotron resonance detection of multiphoton ionization spectroscopy

Fourier transform ion cyclotron resonance (FT-ICR) detection was tested for resonanceenhanced multiphoton ionization (REMPI) spectroscopy. The (2+1) REMPI spectra of acetaldehyde were obtained in the wavelength range 364–354 nm via a two-photon resonant 3s ← n Rydberg transition. The space-charge effects on the REMPI spectra were examined in the vicinity of the 0 ₀ ⁰ transition. The trapping efficiency measurement shows that all the ions produced from REMPI dissociation processes are arrested in the ion cyclotron resonance cell even in the presence of space-charge interactions. Axial kinetic energy release distributions of ions were extracted from the trapping efficiency data obtained under a new space-charge-free condition. FT-ICR peak heights were measured as a function of pressure at different laser powers, magnetic field strengths, and ion excitation methods to test for the detection linearity. The FT-ICR detection responds linearly to the number of ions in a low pressure limit. The product branching ratio was measured by using various ion excitation methods and was compared with the previous quadrupole mass spectrometric study. FT-ICR detection yields the mass-selected REMPI spectra and the product branching ratio in the absence of kinetic shifts.     

琥珀酰胆碱离子在水/邻硝基苯甲醚界面的伏安行为及其离子电极的研究

由于琥珀酰胆碱离子(Sch²⁺)在水(w)和邻硝基苯甲醚(NA)界面的传递半积分半微分循环伏安波与常规新极谱波的特性相似,测定了Δ_w^oφ_1/2、响应斜率、n和D_Sch^w2+.据此制备了以四苯硼琥珀酰胆碱[Sch(TPB)₂]为活性材料、邻硝基苯甲醚和邻苯二甲酸二丁酯(DBPH)为混合溶剂的Sch²⁺-PVC液膜电极.电极特性与Sch²⁺离子在w/NA界面传递所预示的结果相似.试验了电极对某些离子的选择性系数和回收率.