Four New Diterpenoids from Isodon leucophylla

IsodonleucoPhyll(Dunn)Hara(Labiatae),distributedinthenorthwestareaofYunnanProvince,isusedasfolkmedicineforitsantibacterialandanti-inflanimatoryactivitybylocalpractitioners'.Fromtheleavesofthisplant,fournewent-kauranetypediterPenoids,baiyecrystalA'C1'3andePi-baiyecrystalC4,wereisolated.Thispaperpresentstheirsimctureelucidation.BaiyecrystalA1C26H34O1owasdeterminedbyHRMS(5O6.2157,calc5o6.2l52).Itsmassspectrumshowedthatthemolecularion(wt5O6)was58amumorethanthatofeffusaninD5',aknownkaureno…     

Gold Nanoparticle-based Layer-by-Layer Enhancement of DNA Hybridization Electrochemical Signal at Carbon Nanotube Modified Carbon Paste Electrode

Nanoporous materials have been widely applied to biosensor investigation. Recently, Guo et al. have investigated the mesoporous materials modified carbon paste electrode for rapid cTnI (cardiac troponin I) detection with enhanced sensitivity1-3. However, …     

Synthesis and Crystal Structure of (E)2-(3'-Bromo-5'-chloro-salicylidene amino)-4-methyl Pyridine

A new Schiff base compound,2-bromo-4-chloro-6-[(4-methylpyridin-2-ylimino)me-thyl]phenol(C13H10BrClN2O),has been synthesized by the condensation of equimolar 3-bromo-5-chlorosalicylaldehyde and 4-methylpyridin-2-ylamine in a methanol solution.The compound Was characterized by elemental analysis,IR spectra,and single-crystal X-ray diffraction.The crystal belongs to the monoclinic system,space group P21 with a=6.048(3),b=14.063(7),c=7.623(4)(A),β=97.703(7)°,Z=2,V=642.5(6)(A)3,Dc=1.683 g/cm3,Mr=325.59,λ(MoKa)=0.71073(A),μ=3.395 mm-1,F(000)=324,R=0.0370 and wR=0.0662.A total of 3879 reflections were collected,of which 1970 with,I＞2σ(I)were observed.As expected.the molecule adopts a trans configuration about the C=N double bond.The benzene and pyridine rings are nearly coplanar(mean deviation from the combined plane is 0.031(3)(A)),with their dihedral angle of 3.3(3)°.The preliminary biological tests show that the compound has excellent antibacterial activities.     

New tetramic acid derivatives from the deep-sea-derived fungus Cladosporium sp. SCSIO z0025

Eight new tetramic acid derivatives, cladosporiumins A–H (1–8) were isolated from a culture broth of Cladosporium sp. SCSIO z0025 derived from the deep-sea sediment collected from Okinawa Trough. Their structures were elucidated by extensive spectroscopic data analysis. Compounds 1–3 were unique 3-acyltetramic acids with a hexyl enic alcohol side chain and a six-membered lactone ring substituted at C-3 of the 2, 4-pyrrolidinedione skeleton. The absolute configurations of chiral carbons of the 2, 4-pyrrolidinedione unit in 1–4 and 7 were established by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. And the absolute configurations of chiral carbons of the six-membered lactone ring in 1–3 were established by density functional theory calculation of their ¹³C NMR chemical shifts. In addition, all the compounds were tested for cytotoxic, antibacterial, anti-biofilm, and AchE inhibitory activities.     

毛细管电泳电化学法监测甘露糖生产工艺

葡萄糖;葡萄糖酸钙;毛细管电泳电化学法监测甘露糖生产工艺;电化学检测     

一步法合成大孔丙烯酸交联树脂

悬浮聚合;二乙烯苯;一步法合成大孔丙烯酸交联树脂     

Investigation of synchroniser engagement in dual clutch transmission equipped powertrains

Transient response of a dual clutch transmission (DCT) powertrain to synchroniser mechanism engagements is investigated using a lumped inertia model of the powertrain. Original research integrates lumped inertia powertrain models for the DCT with a detailed synchroniser mechanism model and two separate engine models, comprising of a mean torque model and a harmonic torque model, using torque derived from piston firing. Simulations are used to investigate the synchroniser mechanism engagement process in a previously unscrutinised operating environment. Simulations are performed using both engine torque models, with the mean torque model demonstrates the highly nonlinear nature of synchroniser mechanism engagement, and the powertrain response to the engagement process. Through the introduction of harmonic engine torques, additional excitation is present in the mechanism during engagement, and increased vibration of the synchroniser sleeve results. The impact of vibrations is particularly important to the increased wear of indexing chamfer contact surfaces.     

Bi-Lipschitz maps in <Emphasis Type="Italic">Q</Emphasis>-regular Loewner spaces

By applying the theory of quasiconformal maps in measure metric spaces that was introduced by Heinonen-Koskela, we characterize bi-Lipschitz maps by modulus inequalities of rings and maximal, minimal derivatives in Q-regular Loewner spaces. Meanwhile the sufficient and necessary conditions for quasiconformal maps to become bi-Lipschitz maps are also obtained. These results generalize Rohde’s theorem in ℝ ⁿ and improve Balogh’s corresponding results in Carnot groups. This research is supported by China NSF (Grant No. 10271077)     

Application of Nanogold Probe Coupled with Silver Enhancement in Rapid cTnI Colorimetric Immunoassay

Cardiac troponin I (cTnI) in the serum of patients has been established as a principal biochemical marker of myocardial damage1-4. Fast detection of cTnI will be helpful for the diagnosis of acute myocardial infarction (AMI), the identification of myocardial injury (MI) and the stratification of cardiac risk. A number of serological tests have been developed for the detection of cTnI. As known, among many methods, enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) wer…     

Capillary Column Coated with Heptakis（2,3,6-tri-O-octyl）-β-cyclodextrin Using Sol-gel Technology

Heptakis(2,3,6-tri-O-octyl)-β-cyclodextrin was coated onto the fused silica capillary by sol-gel technology.Column efficiency and column selectivity were studied.The results indicated that high ability of separation was acquired.Positional isomers of aromatic compounds were well separated.