Mechanochemical Synthesis of Corannulene-Based Curved Nanographenes.

It is shown that corannulene-based strained π-surfaces can be obtained through the use of mechanochemical Suzuki and Scholl reactions. Besides being solvent-free, the mechanochemical synthesis is high-yielding, fast, and scalable. Therefore, gram-scale preparation can be carried out in a facile and sustainable manner. The synthesized nanographene structure carries positive (bowl-like) and negative (saddle-like) Gaussian curvatures and adopts an overall quasi-monkey saddle-type of geometry. In terms of properties, the non-planar surface exhibits a high electron affinity that was measured by cyclic voltammetry, with electrolysis and in situ UV/vis spectroscopy experiments indicating that the one-electron reduced state displays a long lifetime in solution. Overall, these results indicate the future potential of mechanochemistry in accessing synthetically challenging and functional curved π-systems.

Tuning the reduction potential of quinones by controlling the effects of hydrogen bonding, protonation and proton-coupled electron transfer reactions.

An all-organic cell comprising 2,3-dimethyl-1,4-napthoquinone and pyrano[3,2-f]chromene as electroactive elements exhibited a good combination of large cell voltage and stability of the reduced quinone upon the addition of diethyl malonate (a weak organic acid), as compared to the addition of trifluoroethanol (which led to a high cell potential but low stability via strong hydrogen bonding interactions) and the addition of trifluoroacetic acid (which led to a lower cell potential but high stability through proton transfer).

Higher order spin resonances in a 2.1-GeV/c polarized proton beam.

Spin resonances can depolarize or spin flip a polarized beam. We studied 1st and higher order spin resonances with stored 2.1 GeV/c vertically polarized protons. The 1st order vertical (ν(y)) resonance caused almost full spin flip, while some higher order ν(y) resonances caused partial depolarization. The 1st order horizontal (ν(x)) resonance caused almost full depolarization, while some higher order ν(x) resonances again caused partial depolarization. Moreover, a 2nd order ν(x) resonance is about as strong as some 3rd order ν(x) resonances, while some 3rd order ν(y) resonances are much stronger than a 2nd order ν(y) resonance. One thought that ν(y) spin resonances are far stronger than ν(x), and that lower order resonances are stronger than higher order; the data do not support this.

Narrow spin resonance width and spin flip with an rf-bunched deuteron beam.

We used an rf solenoid to study the widths of rf spin resonances with both bunched and unbunched beams of 1.85 GeV/c polarized deuterons stored in the COSY synchrotron. With the unbunched beam at different fixed rf-solenoid frequencies, we observed only partial depolarization near the resonance. However, the bunched beam's polarization was almost fully flipped; moreover, its resonance was much narrower. We then used Chao's recent equations to explain this behavior and to calculate the polarization's dependence on various rf-solenoid and beam parameters. Our data and calculations indicate that a bunched deuteron beam's polarization can behave as if the beam has zero momentum spread.

Experimental test of a new technique to overcome spin-depolarizing resonances.

We recently tested a new spin resonance crossing technique, Kondratenko Crossing (KC), by sweeping an rf-solenoid's frequency through an rf-induced spin resonance with both the KC and traditional fast crossing (FC) patterns. Using both rf bunched and unbunched 1.85 GeV/c polarized deuterons stored in COSY, we varied the parameters of both crossing patterns. Compared to FC with the same crossing speed, KC reduced the depolarization by measured factors of 4.7 +/- 0.3 and 19_{-5};{+12} for unbunched and bunched beams, respectively. This clearly showed the large potential benefit of Kondratenko Crossing over fast crossing.

Experimental verification of predicted beam-polarization oscillations near a spin resonance.

The Chao matrix formalism allows analytic calculations of a beam's polarization behavior inside a spin resonance. We recently tested its prediction of polarization oscillations occurring in a stored beam of polarized particles near a spin resonance. Using a 1.85 GeV/c polarized deuteron beam stored in the COoler SYnchrotron, we swept a new rf solenoid's frequency rather rapidly through 400 Hz during 100 ms, while varying the distance between the sweep's end frequency and the central frequency of an rf-induced spin resonance. Our measurements of the deuteron's polarization near and inside the resonance agree with the Chao formalism's predicted oscillations.

Achieving 99.9% proton spin-flip efficiency at higher energy with a small RF dipole.

We recently used a new ferrite rf dipole to study spin flipping of a 2.1 GeV/c vertically polarized proton beam stored in the COSY Cooler Synchrotron in Jülich, Germany. We swept the rf dipole's frequency through an rf-induced spin resonance to flip the beam's polarization direction. After determining the resonance's frequency, we varied the frequency range, frequency ramp time, and number of flips. At the rf dipole's maximum strength and optimum frequency range and ramp time, we measured a spin-flip efficiency of 99.92+/-0.04%. This result, along with a similar 0.49 GeV/c IUCF result, indicates that, due to the Lorentz invariance of an rf dipole's transverse integralBdl and the weak energy dependence of its spin-resonance strength, an only 35% stronger rf dipole should allow efficient spin flipping in the 100 GeV BNL RHIC Collider or even the 7 TeV CERN Large Hadron Collider.

Oral thymic extract for chronic hepatitis C in patients previously treated with interferon. A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Hepatitis C is an important cause of chronic liver disease. It is claimed that Complete Thymic Formula, an over-the-counter herbal dietary supplement, is beneficial for patients with hepatitis C. OBJECTIVE: To evaluate the efficacy and safety of Complete Thymic Formula. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Tertiary referral center. PATIENTS: 38 patients with hepatitis C who did not respond to or were intolerant of interferon therapy. INTERVENTION: Complete Thymic Formula for 3 to 6 months or placebo for 3 months. MEASUREMENTS: Serial measurements of hepatitis C virus (HCV) RNA titers. RESULTS: No differences were noted at 3 months between the placebo group (n = 13) and the treatment group (n = 19) in mean HCV RNA titers (4.06 +/- 1.52 x 10(6) copies/mL compared with 3.48 +/- 1.92 x 10(6) copies/mL; P > 0.2). The 19 patients who completed 6 months of treatment with Complete Thymic Formula remained positive for HCV, and their mean HCV RNA titers were similar at 6 months and at baseline (2.78 +/- 1.96 x 10(6) copies/mL compared with 3.12 +/- 1.94 x 10(6) copies/mL; P > 0.2). CONCLUSIONS: Complete Thymic Formula did not benefit patients who had previously received interferon therapy. Patients should be advised about use of this over-the-counter compound.