MRT Letter: Two-Photon Excitation-Based 2pi Light-Sheet System for Nano-Lithography

We propose two-photon excitation-based light-sheet technique for nano-lithography. The system consists of 2 -configured cylindrical lens system with a common geometrical focus. Upon superposition, the phase-matched counter-propagating light-sheets result in the generation of identical and equi spaced nano-bump pattern. Study shows a feature size of as small as few tens of nanometers with a inter-bump distance of few hundred nanometers. This technique overcomes some of the limitations of existing nano-lithography techniques, thereby, may pave the way for mass-production of nano-structures. Potential applications can also be found in optical microscopy, plasmonics, and nano-electronics. Microsc. Res. Tech. 78:1-7, 2015. (c) 2014 Wiley Periodicals, Inc.

Effect of Ni-Zr codoping on dielectric and magnetic properties of SrFe12O19 via sol-gel route

Nanocrystalline strontium hexaferrites SrFe12-2x (Ni2+-Zr4+)(x)O-19] nanoparticles were successfully synthesized by sal gel process. For densification the powders were sintered at 950 degrees C/4 h. The sintered samples were characterized by X-ray diffraction (XRD), surface area measurement, and field emission scanning electron microscope (FESEM). The lattice parameter a is almost constant but c increased with x upto 0.8 and then decreased. The frequency dependent complex permittivity (epsilon and epsilon `' and permeability (mu' and mu `') and magnetic properties such as saturation magnetization (M-s), coercive field (H-c) were studied. If is observed that saturation magnetization increased gradually from 57.82 emuig to 67.2 emufg as x increased from 0.2 to 0.4 and then decreased from 672 emufg to 31.63 ernufg for x=1.0. In present study, x=0.4 shows high value of M-s 67.2 emu/g. The real part of permittivity (epsilon') remains constant upto a frequency 1 GHz and increases further with an increase of frequency, a resonance and anti resonance peak was observed above 1 GHz for all the samples. In real part of permeability (mu') the relaxation frequency is observed above 1 GHz for all the samples and it is attributed to the domain wall motion. It is well known that the permeability for polycrystalline ferrites can be described as the superposition of two different magnetizing mechanisms: spin rotation and domain wall motion. These low coercive strontium hexaferrites are suitable for magnetic recording applications in hard disks, floppy disks, video tapes, etc. (C) 2015 Elsevier B.V. All rights reserved.

Insights into stabilizing interactions in the distorted domain-swapped dimer of Salmonella typhimurium survival protein

The survival protein SurE from Salmonella typhimurium (StSurE) is a dimeric protein that functions as a phosphatase. SurE dimers are formed by the swapping of a loop with a pair of beta-strands and a C-terminal helix between two protomers. In a previous study, the Asp230 and His234 residues were mutated to Ala to abolish a hydrogen bond that was thought to be crucial for C-terminal helix swapping. These mutations led to functionally inactive and distorted dimers in which the two protomers were related by a rotation of 167 degrees. New salt bridges involving Glu112 were observed in the dimeric interface of the H234A and D230A/H234A mutants. To explore the role of these salt bridges in the stability of the distorted structure, E112A, E112A/D230A, E112A/H234A, E112A/D230A/H234A, R179L/H180A/H234A and E112A/R179L/H180A/H234A mutants were constructed. X-ray crystal structures of the E112A, E112A/H234A and E112A/D230A mutants could be determined. The dimeric structures of the E112A and E112A/H234A mutants were similar to that of native SurE, while the E112A/D230A mutant had a residual rotation of 11 degrees between the B chains upon superposition of the A chains of the mutant and native dimers. The native dimeric structure was nearly restored in the E112A/H234A mutant, suggesting that the new salt bridge observed in the H234A and D230A/H234A mutants was indeed responsible for the stability of their distorted structures. Catalytic activity was also restored in these mutants, implying that appropriate dimeric organization is necessary for the activity of SurE.

Future collider signatures of the possible 750 GeV state

If the recent indications of a possible state I broken vertical bar with mass similar to 750 GeV decaying into two photons reported by ATLAS and CMS in LHC collisions at 13 TeV were to become confirmed, the prospects for future collider physics at the LHC and beyond would be affected radically, as we explore in this paper. Even minimal scenarios for the I broken vertical bar resonance and its gamma gamma decays require additional particles with masses . We consider here two benchmark scenarios that exemplify the range of possibilities: one in which I broken vertical bar is a singlet scalar or pseudoscalar boson whose production and gamma gamma decays are due to loops of coloured and charged fermions, and another benchmark scenario in which I broken vertical bar is a superposition of (nearly) degenerate CP-even and CP-odd Higgs bosons in a (possibly supersymmetric) two-Higgs doublet model also with additional fermions to account for the gamma gamma decay rate. We explore the implications of these benchmark scenarios for the production of I broken vertical bar and its new partners at colliders in future runs of the LHC and beyond, at higher-energy pp colliders and at e (+) e (-) and gamma gamma colliders, with emphasis on the bosonic partners expected in the doublet scenario and the fermionic partners expected in both scenarios.