Novel ESIPT inspired benzimidazole, benzoxazole and benzothiazole were synthesized from 2,4-dihydroxy benzoic acid and 1,2-phenelenediamine, 2-aminophenol, and 2-aminothiophenol respectively. The synthesized 2-(2',4'-dihydroxyphenyl) benzimidazole, benzoxazole and benzothiazole are fluorescent and the emission characteristic are very sensitive to the micro-environment. They show a single absorption and dual emission with large Stokes shift originating from excited state intramolecular proton transfer. The absorption-emission characteristics of all these compounds are studied as a function of pH. The change in the electronic transition, energy levels, and orbital diagrams of synthesized compounds were investigated by the molecular orbital calculation and were correlated with the experimental spectral emission. Experimental absorption and emission wavelengths are in good agreement with those predicted using the Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) [B3LYP/6-31G(d)].

Cobalt is used as chemical modifier to improve sensitivity and minimize matrix effects in Cr determinations by tungsten coil atomic emission spectrometry (WCAES). The atomizer is a tungsten filament extracted from microscope light bulbs. A solid-state power supply and a handheld CCD-based spectrometer are also used in the instrumental setup. In the presence of 1000mgL(-1) Co, WCAES limit of detection for Cr (λ=425.4nm) is calculated as 0.070mgL(-1); a 10-fold improvement compared to determinations without Co modifier. The mechanism involved in such signal enhancement is similar to the one observed in ICP OES and ICP-MS determinations of As and Se in the presence of C. Cobalt increases the population of Cr(+) by charge transfer reactions. In a second step, Cr(+)/e(-) recombination takes place, which results in a larger population of excited-state Cr atoms. This alternative excitation route is energetically more efficient than heat transfer from atomizer and gas phase to analyte atoms. A linear dynamic range of 0.25-10mgL(-1) and repeatability of 3.8% (RSD, n=10) for a 2.0mgL(-1) Cr solution are obtained with this strategy. The modifier high concentration also contributes to improving accuracy due to a matrix-matching effect. The method was applied to a certified reference material of Dogfish Muscle (DORM-2) and no statistically significant difference was observed between determined and certified Cr values at a 95% confidence level. Spike experiments with bottled water samples resulted in recoveries between 93% and 112%.

Photochemical water splitting is a promising avenue to sustainable, clean energy and fuel production. Gallium nitride (GaN) and its solid solutions are excellent photocatalytic materials; however, the efficiency of the process is low on pure GaN, and co-catalysts are required to increase the yields. We present the first time-domain theoretical study of the initial steps of photocatalytic water splitting on a GaN surface. Our state-of-the-art simulation technique, combining non-adiabatic molecular dynamics and time-dependent density functional theory, allows us to characterize the mechanisms and timescales of the evolution of the photogenerated positive charge (hole) and the subsequent proton transfer at the GaN/water interface. The calculations show that the hole loses its excess energy within 100 fs and localizes primarily on the nitrogen atoms of the GaN surface, initiating a sequence of proton transfer events from the surface N-H group to the nearby OH groups and bulk water molecules. Water splitting requires hole localization on oxygen rather than nitrogen, necessitating non-adiabatic transitions uphill in energy on pure GaN. Such transitions happen rarely, resulting in low yields of the photocatalytic water splitting observed experimentally. We conclude that efficient co-catalysts should favor localization of the photogenerated hole on oxygen-containing species at the semiconductor/water interface.

We reanalyze transfer-matrix and Monte Carlo results for the critical Binder cumulant U^{*} of an anisotropic two-dimensional Ising model on a square lattice in a square geometry with periodic boundary conditions. Spins are coupled between nearest-neighboring sites and between next-nearest-neighboring sites along one of the lattice diagonals. We find that U^{*} depends only on the asymptotic critical long-distance features of the anisotropy, irrespective of its realization through ferromagnetic or antiferromagnetic next-nearest-neighbor couplings. We modify an earlier renormalization-group calculation to obtain a quantitative description of the anisotropy dependence of U^{*}. Our results support our recent claim towards the validity of universal finite-size scaling for critical phenomena in the presence of a weak anisotropy.

Open-chain pentapyrroles were isolated as side-products from the synthesis of triaryl-corroles and then converted to the corresponding sapphyrins by catalytic oxidation in acidic media. The investigated compounds were characterized by UV-vis and (1)H NMR spectroscopy, mass spectrometry, electrochemistry, and spectroelectrochemistry and are represented as (Ar)4PPyH3 and (Ar)4SH3, where Ar is a F(-) or Cl(-) substituted phenyl group, PPy is a trianion of the open-chain pentapyrrole, and S is a trianion of the sapphyrin. Cyclic voltammetry and thin-layer UV-vis spectroelectrochemistry measurements were carried out in PhCN and CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate. The open-chain pentapyrroles undergo two reversible one-electron reductions and two reversible one-electron oxidations to generate [(Ar)PPyH3](-), [(Ar)PPyH3](2-), [(Ar)PPyH3](+), and [(Ar)PPyH3](2+) which were spectroscopically characterized. The corresponding sapphyrins exhibit two or three reversible one-electron oxidations in PhCN, but the reductions of these compounds are irreversible because of coupled chemical reactions following electron transfer. Comparisons are made between redox potentials and spectral properties of the open-chain pentapyrroles, sapphyrins, and structurally related corroles. Protonation of the open-chain pentapyrroles and sapphyrins was also carried out in CH2Cl2, and equilibrium constants were calculated by monitoring the spectral changes during titrations with trifluoroacetic acid. The pentapyrroles undergo a simultaneous two-proton addition to generate [(Ar)4PPyH5](2+) while the sapphyrins undergo two stepwise single proton additions to give [(Ar)4SH4](+) and [(Ar)4SH5](2+), respectively.

5-methylcytosine (5-mC), an important epigenetic modification involved in development, can be converted enzymatically to 5-hydroxymethylcytosine (5-hmC). 5-hmC is considered an intermediate of active DNA cytosine demethylation and makes itself serve as an epigenetic mark. 5-hmC content in most mammalian cells is low and the quantification of 5-hmC by liquid chromatography-mass spectrometry (LC-MS) frequently suffers from ion suppression by the presence of unmodified nucleosides. To circumvent this problem, we developed a method to selectively transfer a glucosyl group to the hydroxymethyl moiety of 5-hmC and form a more hydrophilic residue (β-glucosyl-5-hydroxymethyl-2'-deoxycytidine, 5-gmdC) by using T4 β-glucosyltransferase. The more hydrophilic 5-gmdC can be selectively enriched by using NH2-silica via hydrophilic interaction prior to liquid chromatography - tandem mass spectrometry (LC-MS/MS) analysis, which eliminates the ion suppression and significantly improves the detection sensitivity and accuracy. Using this method, we successfully quantified 5-hmC content in genomic DNA of three human cell lines and seven yeast strains. To the best of our knowledge, this is the first report about the existence of 5-hmC in the model organism of yeast. In addition, the contents of 5-hmC in two yeast strains of Schizosaccharomyces pombe are even higher than those of 5-mC, indicating that 5-hmC may play important roles on the physiological functions of yeast.

Massachusetts General Hospital miniature pigs (MGH minipigs) have been established for organ transplantation studies across the homozygous major histocompatibility complex, but cloning efficiency of MGH minipigs is extremely low. This study was designed to increase the productivity of MGH minipigs by nuclear transfer of post-thaw donor cells after 1 h co-incubation with roscovitine. The MGH minipig cells were genetically modified with GT KO (alpha1,3-galactosyltransferase knock-out) and hCD46 KI (human CD46 knock-in) and used as donor cells. The GT KO/hCD46 KI donor cells were cultured for either 3 days (control group) or 1 h after thawing with 15 μM roscovitine (experimental group) prior to the nuclear transfer. The relative percentage of the transgenic donor cells that entered into G0/G1 was 93.7 % (±2.54). This was different from the donor cells cultured for 1 h with the roscovitine-treated group (84.6 % ±4.6) (P < 0.05) and without roscovitine (78.6 % ±5.5) (P < 0.01), respectively. The pregnancy rate and delivery rate in the roscovitine group (8/12 and 6/8, respectively) were significantly higher (P < 0.01) than those in the control group (6/19 and 3/6, respectively). In the experimental group, 12 GT KO/hCD46 KI transgenic minipigs were successfully generated, and five minipigs among them survived for more than 6 months so far. The recipient-based individual cloning efficiency ranged from 0.74 to 2.54 %. In conclusion, gene-modified donor cells can be used for cloning of MGH minipigs if the cells are post-thawed and treated with roscovitine for 1 h prior to nuclear transfer.

PURPOSE:

The use of cabergoline and coasting are both effective in reducing the risk of ovarian hyperstimulation syndrome (OHSS). Our aim was to compare the effectiveness of cabergoline with coasting to prevent moderate-severe OHSS.

METHODS:

Fifty-seven consecutive infertile patients (81 cycles) at risk of developing OHSS were enrolled through our computerized IVF database system. Inclusion criteria were: (i) E2 level on the day of human chorionic gonadotrophin (hCG) greater than 3,500 pg/ml; (ii) patients who underwent luteal long GnRH agonist cycle; (iii) patients who used cabergoline for OHSS prevention; (iv) patients who underwent coasting for OHSS prevention. The cabergoline group constituted 17 patients (26 cycles) who started using 0.5 mg oral cabergoline daily for 8 days on the day of hCG, whereas the coasting group constituted 40 patients (55 cycles) who underwent coasting.

RESULTS:

Both groups were comparable regarding the women's mean age, body mass index and duration of infertility. Implantation rate, clinical pregnancy per embryo transfer and miscarriage rates were not different between the two groups. There was no OHSS in the cabergoline group (0 %), whereas there were two OHSS (3.6 %) in the coasting group; however, this difference was not significant.

CONCLUSIONS:

In conclusion, 0.5 mg daily use of cabergoline for 8 days beginning from hCG administration is a very effective way to reduce moderate-severe OHSS without sacrificing pregnancy rates in patients at risk of developing OHSS.

High resolution electronic spectra of 2-phenylindole (PI) and N-phenylcarbazole (PC) have been recorded in the collision-free environment of a molecular beam. Inertial defects determined from fits of the spectra were used to determine the twist angles between the two chromophores and their attached benzene rings in the ground (S0) and excited (S1) electronic states. PI was found to be significantly more planar than PC, especially in the S1 state. Stark-effect measurements of the permanent electric dipole moments of both molecules in both states show that significantly more charge is transferred from the phenyl group to the chromophore in PI (0.13e) than in PC (0.076e) when the photon is absorbed. Thereby demonstrated for the first time is a direct connection between photo-induced geometry change and charge transfer on excitation of an isolated molecule by light.

PURPOSE:

This report describes the effect of periosteal-derived cells transfected with adenovirus-mediated bone morphogenetic protein-2 (BMP-2) on the repair of mandibular defects in rabbits.

MATERIALS AND METHODS:

Periosteal-derived cells were transfected with a replication-defective adenoviral vector encoding BMP-2, and the expression of BMP-2 was examined in transfected cells using in situ hybridization and enzyme-linked immunosorbent assay. In addition, the proliferation ability and activity of alkaline phosphatase of transfected cells were examined using the 3-[4,5-dimethylthiazol-2-Yl]-2,5-diphenyltetrazolium bromide method and enzymology, respectively. In vitro critical-size defects (about 10 × 6 mm) were made bilaterally in each rabbit mandible, and individual sites were implanted with tissue-engineered bone modified with an adenovirus construct encoding the recombinant human BMP-2 gene (Ad-BMP-2), tissue-engineered bone without modification, single bioactive glass ceramic, or no implants (control). New bone formation was evaluated by histochemical stain.

RESULTS:

BMP-2 expression in the supernate of infected cells was detected from the first day after Ad-BMP-2 transfection and remained at a high level for at least 2 weeks. Alkaline phosphatase expression in transfected cells was significantly greater than in uninfected cells. The group of Ad-BMP-2-modified periosteal-derived cells formed more new bone than the other group at any time point.

CONCLUSION:

Gene-modified tissue-engineered bone grafts have greater osteogenic potential than single tissue-engineered bone and single bioactive glass ceramic graft. Ex vivo Ad-BMP-2 transfer to periosteal-derived cells can increase bone formation in critical-size bone defects. Further studies are needed to determine if modified engineered cells can be developed for safe and effective clinical applications.