16-nor Limonoids from Harrisonia perforata as promising selective 11β-HSD1 inhibitors.

Two new 16-nor limonoids, harperspinoids A and B (1 and 2), with a unique 7/5/5/6/5 ring system, have been isolated from the plant Harrisonia perforate together with a known one, Harperforin G (3). Their structures were elucidated by NMR spectroscopy, X-ray diffraction analysis and computational modelling. Compound 1 exists as polymorphic crystals.

Spinal mitochondrial-derived ROS contributes to remifentanil-induced postoperative hyperalgesia via modulating NMDA receptor in rats.

Background: Activation of N-methyl-d-aspartate (NMDA) receptor by reactive oxygen species (ROS) in the spinal cord plays an important role in the development of hyperalgesia in several neuropathic pain models. The study examined the involvement of ROS-NMDA signaling pathway in remifentanil-induced postoperative hyperalgesia.

Methods: Nociceptive responses were measured by paw withdrawal mechanical threshold (PWT) and paw withdrawal thermal latency (PWL) before and up to day 5 after remifentanil infusion.

[Degradation of the absorbed methyl mercaptan by persulfate in alkaline solution].

Methyl mercaptan (CH3SH) is considered to be an important contributor to odors. It is a toxic, corrosive and acid gas. The absorption of CH3SH by alkaline solution is one of the most widely used processes, but the remained solution should be further treated.

[Variation of nitrogen during the high suspended sediments concentration water supply in an artificial shallow lake].

The effect of water quality and suspended sediments in the process of water supply is of an increasing concern recently in an artificial shallow lake. The water supply from the Yellow River to Dongchang Lake happened on April 23rd to 25th, 2012. The synchronous monitoring of flow velocity, suspended sediment concentration, dissolved nitrogen and particulate nitrogen concentration was conducted during the three days in five monitoring sites of the longitudinal profile from inlet to outlet.

[Activated carbon catalyzed persulfate oxidation of azo dye acid orange 7 in aqueous solution].

Persulfate oxidation is a recently emerging advanced oxidation process for the pollution control. Persulfate (PS) degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e. g.

The first genetic map of pigeon pea based on diversity arrays technology (DArT) markers.

With an objective to develop a genetic map in pigeon pea (Cajanus spp.), a total of 554 diversity arrays technology (DArT) markers showed polymorphism in a pigeon pea F(2) mapping population of 72 progenies derived from an interspecific cross of ICP 28 (Cajanus cajan) and ICPW 94 (Cajanus scarabaeoides). Approximately 13% of markers did not conform to expected segregation ratio.

Chemical constituents from fruits of Harrisonia perforata.

Eight limonoids (1-8) including three A, B and D-seco-16-nor-type ones, 5,6-dehydrodesepoxyharperforin C2 (1), harrpernoid B (2), and its C-9S epimer, harrpernoid C (3), along with six known compounds (9-14), were isolated from fruits of Harrisonia perforata. Extensive spectroscopic analysis was used to elucidate their structures and stereochemistries. Further confirmation of structures of 1 and 2 were obtained by single-crystal X-ray diffraction.

[Chloride interference in the determination of COD of landfill leachate].

Chemical oxidation demand (COD) is one of the most important determination indicators of landfill leachate. However, the presence of high concentration chloride in leachate generates interference, which hasn't caused enough concern. The objective of this paper is to compare anti-interference ability of chloride among potassium dichromate reflux method, rapid digestion-spectrophotometric method, basic potassium permanganate method and UV spectrophotometry method.

Chemical constituents from the leaves and stems of Schisandra rubriflora.

Six new nortriterpenoids, schirubridilactones A-F (1-6), as well as 14 known compounds, were isolated from the leaves and stems of Schisandra rubriflora. The structures of 1-6 were elucidated on the basis of spectroscopic methods including HSQC, HMBC, (1)H-(1)H COSY, and ROESY NMR experiments. The relative stereochemistry of 1 was confirmed through single-crystal X-ray analysis.

Lactones from Angiopteris caudatiformis.

Angiopterlactones A (1) and B (2), two unique lactones, and three known lactones, osmundalactone (3), osmundalin (4), and 3,5-dihydroxy-gamma-caprolactone (5), have been isolated from the rhizome of Angiopteris caudatiformis. The structures of 1 and 2 were determined by NMR and MS methods, and the structure of 2 was confirmed by X-ray crystallography. The absolute configurations of 1 and 2 were assigned by application of the CD excitation chirality method and the modified Mosher's method.

Selaginellin A and B, two novel natural pigments isolated from Selaginella tamariscina.

Two new unusual natural pigments were first isolated from the whole herbs of Selaginella tamariscina. The structure of selaginellin A (1) was established as (R,S)-4-[(4'-hydroxy-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]-2,5-cyclohexadien-1-one and selaginellin B (2) as (R,S)-4-[(4'-methoxy-4-(methyl)-3-((4-methoxyphenyl)ethynyl)biphenyl-2-yl)(4-methoxyphenyl)methylene]-2,5-cyclohexadien-1-one, along with four known biflavonoids, amentoflavone (3), hinokiflavone (4), heveaflavone (5), and 7''-O-methylamentoflavone (6). Their chemical structures were elucidated by spectral analysis of electrospray ionization mass spectroscopy (ESI-MS), one-dimensional nuclear magnetic resonance spectroscopy (1D-NMR) and two-dimensional-nuclear magnetic resonance spectroscopy (2D-NMR) including (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer (DEPT) and heteronuclear multiple bond coherence (HMBC), and single-crystal X-ray diffraction techniques.

Role of the reduction site in the fluorinated or sulfated TiO2 photocatalytic process.

In this article, the effects of TiO2 surface fluorination and sulfation, on the active oxygen species formed at the reduction site in the photocatalytic process, namely O2*- and H2O2, were investigated from a new perspective. The superoxide radical, (O2*-), was determined by colorimetry of nitroblue tetrazolium, a prominent O2*- scavenger. Hydrogen peroxide (H2O2) was estimated by using the iodide-starch method.

Enhanced photocatalytic activity of TiO2 by surface fluorination in degradation of organic cationic compound.

Experiments were carried out to investigate the influence of TiO2 surface fluorination on the photodegradation of a representative organic cationic compound, Methylene Blue (MB). The electropositive MB shows poor adsorption on TiO2 surface; its degradation performs a HO-radical-mediated mechanism. In the F-modified system, the kinetic reaction rate enlarged more than 2.

Involvement of chloride anion in photocatalytic process.

The effect of Cl- on photocatalytic degradation (PCD) of pollutants is an important factor since it is ubiquitous in nature. In general, Cl- showed an inhibition on photodegradation due to its scavenging HO* radicals. In this paper, experiments were carried out to examine the effects of Cl- on the PCD of Methylene Blue (MB) and Orange II (OII) in aqueous TiO2 suspensions under UV light illumination.