Fluorescence and persistent spectral hole burning of Eu in Ge-Ga-S-KBr glasses

Fluorescence and efficient persistent spectral hole burning of Eu³⁺ at 77 K were observed in chalcohalide glasses. The depth of the hole was approximately 30% after a burning process of 1 min with 50 mW power, and it was completely erased with Ar⁺ laser irradiation. The hole survived room temperature heat treatment and showed good thermal stability. The hole-burning mechanism was most probably the photo-reduction of Eu³⁺→Eu²⁺. Fluorescence from Eu³⁺ decreased with increasing temperature and disappeared at the temperature above ∼130 K.     

Convenient palladium-catalyzed homocoupling of iodoarenes in an ionic liquid

Symmetrical functionalized biaryls are obtained in good yields via TDAE/Pd-promoted homocoupling reaction of iodoarenes using the ionic liquid, [bmim]PF₆, as the solvent. The catalyst could be recycled and reused four times in this reaction.     

Synthesis, molecular structure, and polymerization reactivity of ethylenebis(1,3-dimethylcyclopentadienyl)zirconium dichloride

An ethylene-bridged zirconocene complex bearing methyl substituents only on the cyclopentadienyl carbons adjacent to bridge point, ethylenebis(1,3-dimethylcyclopentadienyl)zirconium dichloride (5) was synthesized. Crystal structure of 5 was determined. The complex, 5, when activated with MAO, shows better comonomer incorporation ability than [Ph₂C(Fluo)(Cp)]ZrCl₂ in the ethylene–norbornene copolymerization but it is not better than rac-Et(Ind)₂ZrCl₂ for the ethylene-1-hexene copolymerization in terms of activity and comonomer incorporation.     

Determination of absolute stereochemistry of panaxynol

Absolute stereochemistry of panaxynol was determined by exciton chirality method. The circular dichroism spectra of panaxynol p-bromobenzoate and p-dimethylaminobenzoate show the negative exciton chirality at λ_ext indicating the S configuration of the chiral center.     

Simultaneous determination of raltegravir and raltegravir glucuronide in human plasma by liquid chromatography-tandem mass spectrometric method

Raltegravir is a highly efficacious inhibitor of HIV integrase. Large pharmacokinetic variability has been reported in clinical trials and this could be due to glucuronidation of raltegravir, the only reported metabolism pathway. In order to precisely evaluate and monitor the raltegravir and raltegravir glucuronide simultaneously, a novel, sensitive and robust liquid chromatography-tandem mass spectrometric method was developed and validated for simultaneous determination of raltegravir and raltegravir glucuronide in human plasma. A simple protein precipitation with acetonitrile was utilized for plasma sample preparation prior to analysis. Baseline chromatographic separation was achieved on a ZORBAX Eclipse XDB-C8 using gradient elution mode. The run time was 9 min at a constant flow rate of 0.4 ml/min. The mass spectrometer was operated under a positive electrospray ionization condition. Excellent linearity (r(2) ≥ 0.9997) was achieved for raltegravir and raltegravir glucuronide in the range of 2-2000 nmol/l. The average recovery of raltegravir and raltegravir glucuronide was 105.8% and 102.2%, respectively. The precision (coefficient of variation) was 1.6-6.6% for raltegravir and 2.1-6.9 for raltegravir glucuronide, respectively. The accuracy was 98.6-106.1% for raltegravir and 96.3-100.3% for raltegravir glucuronide. The plasma samples were tested to be stable after nine freeze-thaw cycles and exposure to room temperature for 24 h. This well-validated assay was applied for the quantification of raltegravir and raltegravir glucuronide in plasma samples within 24 h after a single oral dose of 400 mg raltegravir in six healthy subjects.     

Hole transport in sensitized CdS-NiO nanoparticle photocathodes

A general chemical approach was used to synthesise NiO-CdS core-shell nanoparticle films as photocathodes for p-type semiconductor-sensitized solar cells. Compared to dye-sensitized NiO photocathodes, the CdS-sensitized NiO cathodes exhibited two orders of magnitude faster hole transport (attributable to the passivation of surface traps by the CdS) and almost 100% charge-collection efficiencies.     

Synthesis of titania embedded silica hollow nanospheres via sonication mediated etching and re-deposition

Titania embedded silica hollow nanospheres were synthesized from sonication-mediated etching and re-deposition of silica/titania core/shell nanospheres. The designed structure of the hollow nanospheres was proved to be a key factor for the charge trapping/detrapping and resulting bistability in non-volatile organic bistable memory devices (OBDs).     

A two-photon fluorescent probe for ratiometric imaging of hydrogen peroxide in live tissue

We report a two-photon fluorescent probe (PN1) that can be excited by 750 nm femto-second pulses, shows high photostability and negligible toxicity, and can visualize H(2)O(2) distribution in live cells and tissue by two-photon microscopy.     

Genome-wide scan of granular corneal dystrophy, type II: confirmation of chromosome 5q31 and identification of new co-segregated loci on chromosome 3q26.3

Granular corneal dystrophy, type II (CGD2; Avellino corneal dystrophy) is the most common corneal dystrophy among Koreans, but its pathophysiology is still poorly understood. Many reports showed that even though the causative mutation is the same TGFBI R124H mutation, there are severe and mild phenotypes of the corneal dystrophy. We also observed the phenotype differences in our samples. For this reason, we focused our effort on the identification of unknown genetic factor related to phenotype variation. A total 551 individuals from 59 families were genotyped with SNP chip and used in genome-wide linkage analysis. From single-point linkage analyses, we confirmed the known 5q31 region for TGFBI gene, and selected novel nine candidate loci for CGD2. In simulation analysis, the only 3q26.3 region including neuroligin 1 gene (NLGN1) was supported by empirical statistic significance. To investigate the effect of genetic heterogeneity in linkage analysis, we classified CGD2 families into two subgroups. Although we could not find a significant evidence for correlation between the 3q26.3 region and CGD2 phenotypes, this first genome-wide analysis with CGD2 families in Korea has a very important value for offering insights in genetics of CGD2. In addition, the co-segregating loci with CGD2 including 3q26.3 would be a good target for further study to understand the pathophysiology of CGD2.     

Higher infiltration by Th17 cells compared with regulatory T cells is associated with severe acute T-cell-mediated graft rejection

The aim of this study was to evaluate whether the Th17 and Treg cell infiltration into allograft tissue is associated with the severity of allograft dysfunction and tissue injury in acute T cell-mediated rejection (ATCMR). Seventy-one allograft tissues with biopsy-proven ATCMR were included. The biopsy specimens were immunostained for FOXP3 and IL-17. The allograft function was assessed at biopsy by measuring serum creatinine (Scr) concentration, and by applying the modified diet in renal disease (MDRD) formula, which provides the estimated glomerular filtration rate (eGFR). The severity of allograft tissue injury was assessed by calculating tissue injury scores using the Banff classification. The average numbers of infiltrating Treg and Th17 cells were 11.6 ± 12.2 cells/mm2 and 5.6 ± 8.0 cells/mm2, respectively. The average Treg/Th17 ratio was 5.6 ± 8.2. The Treg/Th17 ratio was significantly associated with allograft function (Scr and MDRD eGFR) and with the severity of interstitial injury and tubular injury (P < 0.05, all parameters). In separate analyses of the number of infiltrating Treg and Th17 cells, Th17 cell infiltration was significantly associated with allograft function and the severity of tissue injury. By contrast, Treg cell infiltration was not significantly associated with allograft dysfunction or the severity of tissue injury. The results of this study show that higher infiltration of Th17 cell compared with Treg cell is significantly associated with the severity of allograft dysfunction and tissue injury.