High-rhoR implosions for fast-ignition fuel assembly

Thick, 40 microm plastic shells filled with 25-35 atm of D2 or D3He were imploded on a low-adiabat (alpha approximately 1.3) and with a low-implosion velocity ( approximately 2 x 10(70 cm/s) on the OMEGA laser to generate massive cores of compressed plasma with high areal densities optimal for fast ignition. The targets are driven by 20-kJ relaxation adiabat-shaping laser pulses to keep the inner portion of the shell nearly Fermi degenerate. The measured kinetic energy downshift of proton spectra is in good agreement with the theoretical predictions yielding burn-averaged areal densities of 0.130+/-0.017 g/cm2 and peak rhoR during the burn of about 0.24+/-0.018 g/cm2, the largest rhoR measured on OMEGA to date. The same implosions with empty plastic shells are expected to reach 1.3 g/cm2 across the core (i.e., 2rhoR) enough to stop fast electrons with energies up to 4.5 MeV typical of fast ignition scenarios.     

Stable and continuous wavelength tuning of a hybrid semiconductor laser with an erbium-doped fiber external cavity

We present an experimental study of tuning characteristics and wavelength stability of a 1490 nm doped fiber external cavity laser. The standing wave in the erbium-doped fiber in an external-cavity laser causes spatial hole burning and absorption modulation and forms a dynamic grating. The dynamic grating can effectively suppress side modes and eliminate wavelength fluctuations in the laser. The operating wavelength of this hybrid laser is shown for the first time to our knowledge to be smoothly tunable by changing the semiconductor laser drive current or temperature.     

Highly selective 4-amino-1,8-naphthalimide based fluorescent photoinduced electron transfer (PET) chemosensors for Zn(II) under physiological pH conditions

The design and synthesis of two novel fluorescent sensors based on the photoinduced electron transfer (PET) concept, and , for the detection of zinc under competitive media is described. These sensors are based on the 4-amino-1,8-naphthalimide fluorophore, which has an absorption band centred at 450 nm and emits in the green with lambda(max) approximately 550 nm. By functionalizing the chromophore with a simple benzyl or ethyl-aryl based iminodiacetate receptor at the 4-position, both high selectivity and sensitivity were achieved for the sensing of Zn(II) over other competitive transition and Group I and II metal ions. These sensors were also shown to be pH independent, with a pKa of 2.3 being determined for , which allows these to be used in highly competitive pH media. Upon sensing of Zn(II) the fluorescence emission spectrum is 'switched on' demonstrating the suppression of PET from the receptor to the fluorophore. For , the sensing of Zn(II) was achieved with Kd = 4 nM when measured in pH 7.4 buffered solution, in the presence of 1.1 mM of EGTA.     

Green synthesis and anticancer activity of tetrahydrodipyrazolo[3,4-b:4′,3′-e]pyridines catalyzed by phospho sulfonic acid

Biologically portent/significant tetrahydrodipyrazolo[3,4-b:4′,3′-e]pyridines are synthesized by an efficient green synthesis of various aldehydes with 3-methyl-1H-pyrazol-5(4H)-one in ammonium acetate using phospho sulfonic acid as a solid catalyst under microwave-assisted interaction under solvent-free conditions at 70°C. This methodology is easy to handle and get good to excellent yields. Later the potential in vitro antiproliferation of the titled compounds is evaluated. Among all the titled compounds, 4s and 4t showed the most potent anticancer potentiality on the used cancer cell lines of SK-BR-3 and HeLa (IC₅₀ = 10.70 ± 0.27 and 12.58 ± 0.38, and 19.38 ± 0.32 and 21.55 ± 0.41 μg/mL for SK-BR-3 cells lines and HeLa cells lines, respectively), which were comparable to the positive control.     

Synthesis and self aggregation properties of ester-functionalized heterocyclic pyrrolidinium surfactants

Linear fatty alcohols on reaction with chloro/bromo acetic acid in the presence of catalytic amount of p-toluene sulphonic acid monohydrate under solvent-free conditions are converted into alkyl-2-haloacetate which on reaction with N-methyl pyrrolidine gives ester-functionalized pyrrolidinium surfactants. Thus, new series of ester-functionalized heterocyclic pyrrolidinium head group containing cationic surfactants have been synthesized by green approach via energy saving and cost effective methodology. These new surfactants have been investigated for their surface properties by surface tension, conductivity, and fluorescence method. Surface properties of these surfactants have been found to be far better compared to conventional heterocyclic cationic surfactants having similar hydrophobic alkyl chain length.