Tubular microporous organic networks bearing imidazolium salts and their catalytic CO2 conversion to cyclic carbonates

Tubular microporous organic networks bearing imidazolium salts (T-IM) were prepared by Sonogashira coupling of tetrakis(4-ethynylphenyl)methane and diiodoimidazolium salts, which showed promising catalytic activities in heterogeneous conversion of CO(2) into cyclic carbonates.     

Barrier effect of dendrons on TiO2 particles in dye sensitized solar cells

The short circuit current of dye sensitised solar cells increased significantly by the simple addition of polyester hydroxyl acetylene bis(hydroxymethyl)propanoic acid dendrons on TiO(2) nanoparticles, resulting in a very high overall energy conversion efficiency.     

A pellet-type optical nanomaterial of silica-based naphthalimide-DPA-Cu(II) complexes: recyclable fluorescence detection of pyrophosphate

A pellet-type nanomaterial prepared from a mesoporous silica-immobilized naphthalimide-DPA-Cu(II) complex (MSIND-Cu) is investigated as a selective fluorescent chemosensor for PPi detection with a large "off-on" fluorescence change, low detection limit, short response time and a broad pH test range.     

Isoconiferoside, a new phenolic glucoside from seeds of Panax ginseng

A new phenolic glucoside, isoconiferoside (1), was isolated from the seeds of Panax ginseng (Araliaceae). The structure was determined to be 9-O-[β-D-glucopyranosyl-(1 --> 6)-β-D-glucopyranosyl]-trans-coniferyl alcohol based on spectroscopic analyses (1H- and 13C-NMR, DEPT, COSY, HMQC, and HMBC) and acid hydrolysis.     

Corydaline inhibits multiple cytochrome P450 and UDP-glucuronosyltransferase enzyme activities in human liver microsomes

Corydaline is a bioactive alkaloid with various antiacetylcholinesterase, antiallergic, and antinociceptive activities found in the medicinal herb Corydalis Tubers. The inhibitory potential of corydaline on the activities of seven major human cytochrome P450 and four UDP-glucuronosyltransferase enzymes in human liver microsomes was investigated using LC-tandem MS. Corydaline was found to inhibit CYP2C19-catalyzed S-mephenytoin-4'-hydroxylatoin and CYP2C9-catalyzed diclofenac 4-hydroxylation, with K(i) values of 1.7 and 7.0 mM, respectively. Corydaline also demonstrated moderate inhibition of UGT1A1-mediated 17b-estradiol 3-glucuronidation and UGT1A9-mediated propofol glucuronidation with K(i) values of 57.6 and 37.3 mM, respectively. In the presence of corydaline, CYP3A-mediated midazolam hydroxylation showed a decrease with increasing preincubation time in a dose-dependent manner with K(i) values of 30.0 mM. These in vitro results suggest that corydaline should be evaluated for potential pharmacokinetic drug interactions in vivo due to potent inhibition of CYP2C19 and CYP2C9.     

Development of fluorescent glucose bioprobes and their application on real-time and quantitative monitoring of glucose uptake in living cells

We developed a novel fluorescent glucose bioprobe, GB2-Cy3, for the real-time and quantitative monitoring of glucose uptake in living cells. We synthesized a series of fluorescent glucose analogues by adding Cy3 fluorophores to the α-anomeric position of D-glucose through various linkers. Systematic and quantitative analysis of these Cy3-labeled glucose analogues revealed that GB2-Cy3 was the ideal fluorescent glucose bioprobe. The cellular uptake of this probe competed with the cellular uptake of D-glucose in the media and was mediated by a glucose-specific transport system, and not by passive diffusion. Flow cytometry and fluorescence microscopy analyses revealed that GB2-Cy3 is ten times more sensitive than 2-NBDG, a leading fluorescent glucose bioprobe. GB2-Cy3 can also be utilized for the quantitative flow cytometry monitoring of glucose uptake in metabolically active C2C12 myocytes under various treatment conditions. As opposed to a glucose uptake assay performed by using radioisotope-labeled deoxy-D-glucose and a scintillation counter, GB2-Cy3 allows the real-time monitoring of glucose uptake in living cells under various experimental conditions by using fluorescence microscopy or confocal laser scanning microscopy (CLSM). Therefore, we believe that GB2-Cy3 can be utilized in high-content screening (HCS) for the discovery of novel therapeutic agents and for making significant advances in biomedical studies and diagnosis of various diseases, especially metabolic diseases.     

BINOL-based azacrown ether catalyzed enantioselective Michael addition: asymmetric synthesis of α-aminophosphonates

Several novel 1,1′-bi-2-naphthyl-appended azacrown ethers with donor side-arms were synthesized and applied for the first time as chiral catalysts in the asymmetric Michael addition of an N-protected aminomethylenephosphonate onto acrylonitriles, resulting in high diastereoselectivity and enantioselectivity. The absolute configuration of the adduct was determined from its experimental and calculated CD spectra.     

Recognition of amino acids by functionalized calixarenes

The calixarenic receptors exhibit remarkable host-guest properties towards biologically relevant guests. Aspects of complex formation reactions between both native and derivatized amino acids, di-and tripeptides with calixarenic (chiral or not) receptors are summarized in this critical review. Thus, the discussions emphasize the parameters that affect the molecular binding selectivity and efficiency of functionalized calix[n]arenes towards these substrates. A brief survey on their application in separation of amino acids is also considered (123 references).     

Operation of industrial-scale electron beam wastewater treatment plant

Textile dyeing processes consume large amount of water, steam and discharge filthy and colored wastewater. A pilot scale e-beam plant with an electron accelerator of 1 MeV, 40 kW had constructed at Daegu Dyeing Industrial Complex (DDIC) in 1997 for treating 1,000 m³ per day. Continuous operation of this plant showed the preliminary e-beam treatment reduced bio-treatment time and resulted in more significant decreasing TOC, COD_Cr, and BOD₅. Convinced of the economics and efficiency of the process, a commercial plant with 1 MeV, 400 kW electron accelerator has constructed in 2005. This plant improves the removal efficiency of wastewater with decreasing the retention time in bio-treatment at around 1 kGy. This plant is located on the area of existing wastewater treatment facility in DDIC and the treatment capacity is 10,000 m³ of wastewater per day. The total construction cost for this plant was USD 4 M and the operation cost has been obtained was not more than USD 1 M per year and about USD 0.3 per each m³ of wastewater.     

Enhanced formation of quercetin by combined use of gamma ray and H2O2 from cyanidin-3-O-xylosylrutinoside

Cyanidin-3-O-xylosylrutinoside (cya-3-O-xylrut), a major pigment in Schizandra chinensis Baillon, was effectively removed by gamma irradiation of greater than 2 kGy, whereas quercetin, the most abundant of the flavonoids and has anti-inflammatory and anti-allergic effects, could be generated by degradation of cya-3-O-xylrut. In the present study, we investigated the effect of combination treatment of gamma irradiation and hydrogen peroxide (H₂O₂) on the formation of quercetin through the degradation of cya-3-O-xylrut. Cya-3-O-xylrut was significantly degraded (～93%) by gamma irradiation at 2 kGy and it was completely removed by a combination treatment (0.2% H₂O₂ and 2 kGy gamma ray). The formation of quercetin was significantly appeared at 2 kGy of gamma ray, together with disappearance of cya-3-O-xylrut. The quercetin formation by gamma ray is 3.2 μg/ml and combination treatment is 7.7 μg/ml. Therefore, the combination treatment of H₂O₂ and gamma ray is more effective to convert cya-3-O-xylrut into quercetin than gamma irradiation only. In conclusion, gamma ray combined with H₂O₂ would be a promising tool for bio-conversion of organic compounds.