A conjugated polyazine containing diketopyrrolopyrrole for ambipolar organic thin film transistors

A π-conjugated polyazine containing diketopyrrolopyrrole (DPP) moiety, PDBTAZ, is synthesized through a simple condensation polymerization. PDBTAZ is found to be a high-performance ambipolar semiconductor in organic thin film transistors (OTFTs), showing an electron mobility of up to 0.41 cm(2) V(-1) s(-1) and a hole mobility of up to 0.36 cm(2) V(-1) s(-1).     

Electron tunneling pathways and role of adenine in repair of cyclobutane pyrimidine dimer by DNA photolyase

Electron tunneling pathways in enzymes are critical to their catalytic efficiency. Through electron tunneling, photolyase, a photoenzyme, splits UV-induced cyclobutane pyrimidine dimer into two normal bases. Here, we report our systematic characterization and analyses of photoinitiated three electron transfer processes and cyclobutane ring splitting by following the entire dynamical evolution during enzymatic repair with femtosecond resolution. We observed the complete dynamics of the reactants, all intermediates and final products, and determined their reaction time scales. Using (deoxy)uracil and thymine as dimer substrates, we unambiguously determined the electron tunneling pathways for the forward electron transfer to initiate repair and for the final electron return to restore the active cofactor and complete the catalytic photocycle. Significantly, we found that the adenine moiety of the unusual bent flavin cofactor is essential to mediating all electron-transfer dynamics through a superexchange mechanism, leading to a delicate balance of time scales. The cyclobutane ring splitting takes tens of picoseconds, while electron-transfer dynamics all occur on a longer time scale. The active-site structural integrity, unique electron tunneling pathways, and the critical role of adenine ensure the synergy of these elementary steps in this complex photorepair machinery to achieve maximum repair efficiency which is close to unity. Finally, we used the Marcus electron-transfer theory to evaluate all three electron-transfer processes and thus obtained their reaction driving forces (free energies), reorganization energies, and electronic coupling constants, concluding that the forward and futile back-electron transfer is in the normal region and that the final electron return of the catalytic cycle is in the inverted region.     

Effects of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal injuries in Sprague-Dawley rats

Current anti-gastric ulcer agents have side effects, despite the progression and expansion of advances in treatment. This study aimed to investigate the gastroprotective mechanisms of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal ulcers in rats. For this purpose, Sprague Dawley rats were randomly divided into five groups: Group 1 (normal control) rats were orally administered with vehicle (carboxymethyl cellulose), Group 2 (ulcer control) rats were also orally administered with vehicle. Group 3 (positive control) rats were orally administered with 20 mg/kg omeprazole, Groups 4 and 5 (experimental groups) received ethanol extract of Pithecellobium jiringa ethanol extract at a concentration of 250 and 500 mg/kg, respectively. Sixty minutes later, vehicle was given orally to the normal control group, and absolute ethanol was given orally to the ulcer control, positive control and experimental groups to generate gastric mucosal injury. The rats were sacrificed an hour later. The effect of oral administration of plant extract on ethanol-induced gastric mucosal injury was studied grossly and histology. The level of lipid peroxidation (malondialdehyde-MDA), superoxide dismutase (SOD) and gastric wall mucus were measured from gastric mucosal homogenate. The ulcer control group exhibited severe gastric mucosal injury, and this finding was also confirmed by histology of gastric mucosa which showed severe damage to the gastric mucosa with edema and leucocyte infiltration of the submucosal layer. Pre-treatment with plant extract significantly reduced the formation of ethanol-induced gastric lesions, and gastric wall mucus was significantly preserved. The study also indicated a significant increase in SOD activity in gastric mucosal homogenate, whereas a significant decrease in MDA was observed. Acute toxicity tests did not show any signs of toxicity and mortality up to 5 g/kg. The ulcer protective effect of this plant may possibly be due to its preservation of gastric wall mucus along with increased SOD activity and reduction of oxidative stress (MDA). The extract is non-toxic, even at relatively high concentrations.     

Continuum theory of nanostructure decay via a microscale condition

The morphological relaxation of faceted crystal surfaces is studied via a continuum approach. Our formulation includes (i) an evolution equation for the surface slope that describes step line tension, g1, and step repulsion energy, g3; and (ii) a condition at the facet edge (a free boundary) that accounts for discrete effects via the collapse times, t(n), of top steps. For initial cones and t(n) approximately t(n)4, we use t(g) from step simulations and predict self-similar slopes in agreement with simulations for any g = g3/g1 > 0. We show that for g > 1, (i) the theory simplifies to an equilibrium-thermodynamics model; (ii) the slope profiles reduce to a universal curve; and (iii) the facet radius scales as g(-3/4).     

Measurement of the branching fraction, polarization, and asymmetry for decays, and determination of the Cabibbo-Kobayashi-Maskawa phase

We have measured the branching fraction , longitudinal polarization fraction f(L), and CP asymmetry coefficients A and S for B(0) --> rho(+) rho(-) decays with the Belle detector at the KEKB e(+) e(-) collider using 253 Fb(-1) of data. We obtain B = [22.8 +/- 3.8(stat)(+2.3)(-2.6)(syst)] x 10(-6), f(L) = 0.941 (+0.034)(-0.040)(stat) +/- 0.030(syst). A = 0.00 +/- 0.30(stat) +/- 0.09(syst) and S = 0.08 +/- 0.09(syst). These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase ; the solution consistent with the standard model is phi(2) = (88 +/- 17) degrees or 59 degrees < phi(2) < 115 degrees at 90% C.L.     

The duality problem for the Class of b-weakly compact operators

We establish necessary and sufficient conditions under which b-weakly compact operators between Banach lattices have b-weakly compact adjoints or operators with b-weakly compact adjoints are themselves b-weakly compact. Also, we give some consequences.      

Quantum Secret Sharing with Error Correction

We investigate in this work a quantum error correction on a five-qubits graph state used for secret sharing through five noisy channels. We describe the procedure for the five, seven and nine qubits codes. It is known that the three codes always allow error recovery if only one among the sent qubits is disturbed in the transmitting channel. However, if two qubits and more are disturbed, then the correction will depend on the used code. We compare in this paper the three codes by computing the average fidelity between the sent secret and that measured by the receivers. We will treat the case where, at most, two qubits are affected in each one of five depolarizing channels.     

Short echo time in vivo prostate ¹H-MRSI

Visualization of short echo time (TE) metabolites in prostate magnetic resonance spectroscopic imaging is difficult due to lipid contamination and pulse timing constraints. In this work, we present a modified pulse sequence to permit short echo time (TE=40ms) acquisitions with reduced lipid contamination for the detection of short TE metabolites. The modified pulse sequence employs the conformal voxel MRS (CV-MRS) technique, which automatically optimizes the placement of spatial saturation planes to adapt the excitation volume to the shape of the prostate, thus reducing lipid contamination in prostate magnetic resonance spectroscopic imaging (MRSI). Metabolites were measured and assessed using a modified version of LCModel for analysis of in vivo prostate spectra. We demonstrate the feasibility of acquiring high quality spectra at short TEs, and show the measurement of short TE metabolites, myo-inositol, scyllo-inositol, taurine and glutamine/glutamate for both single and multi-voxel acquisitions. In single voxels experiments, the reduction in TE resulted in 57% improvement in the signal-to-noise ratio (SNR). Additional 3D MRSI experiments comparing short (TE=40 ms), and long (TE=130 ms) TE acquisitions revealed a 35% improvement in the number of adequately fitted metabolite peaks (775 voxels over all subjects). This resulted in a 42 ± 24% relative improvement in the number of voxels with detectable citrate that were well-fitted using LCmodel. In this study, we demonstrate that high quality prostate spectra can be obtained by reducing the TE to 40 ms to detect short T2 metabolites, while maintaining positive signal intensity of the spin-coupled citrate multiplet and managing lipid suppression.     

Design and construction of Q-switched Nd:YAG laser system for LIBS measurements

A passive, Q-switched pulsed, Nd:YAG laser system was designed and built, which can provide a potential compact robust laser source for portable laser induced breakdown spectroscopy systems.The developed laser system operates at 1064 nm. Each laser shot contains a train of pulses having maximum total output energy of 170 mJ. The number of pulses varies from 1–6 pulses in each laser shot depending on the pump energy. The pulse width of each pulse ranges from 20 to 30 ns. The total duration of the output pulse train is within 300 μs. The multi-pulse nature of the laser shots was employed to enhance the LIBS signal. To validate the system, LIBS measurements and analysis were performed on ancient ceramic samples collected from Al-Fustat excavation in Old Cairo. The samples belong to different Islamic periods in Egypt history. The results obtained are highly indicative that useful information can be provided to archeologists for use in restoring and repairing of precious archeological objects.