Determination of methylparaben from cosmetic products by ultra performance liquid chromatography

A new method for the determination of methylparaben by ultra-performance liquid chromatography (UPLC) was developed. Methylparaben is often used as preservative, alone or in combination with other parabens, being added to cosmetic products, pharmaceutical products and foods to avoid microbial contamination. Due to its widespread use and potential risk to human health, assessing human exposure to this compound is of interest. A good determination and quantification of methylparaben was developed with a gradient elution using a mixture of methanol and water (60:40, v/v) within 1.455 min. Under optimized conditions, the linear working range extends over two orders of magnitude with relative standard deviations of intra- and inter-day precision below 2.3 %, and a detection limit of 0.02 ng μL-1 for methylparaben. The proposed method was successfully applied to the assay of methylparaben in cosmetic products with minimal sample preparation

Dynamic adsorption characteristics of thin layered activated charcoal materials used in chemical protective overgarments

The efficiency of a thin layered activated charcoal material used in chemical protective overgarments has been evaluated. The study has been conducted with the aim to obtain protective materials with best characteristics considering resistance to benzene effect under dynamic conditions and to create a new filtration protection device. In order to evaluate dynamic adsorption characteristics of thin layered sorption materials, sophisticated dynamic gas chromatography method is used. The curves of benzene penetration are determined for sandwich materials, and sorption layers used in filtrating protective clothing shows that thin layered carbon sorption materials (type MOO) have good protective properties as compared to other similar materials. The findings will help to create conditions for developing a functional model for producing a new protective overgarment in the near future

ESI, a new Keck Observatory echellette spectrograph and imager

The Echellette Spectrograph and Imager (ESI) is a multipurpose instrument which has been delivered by the Instrument Development Laboratory of Lick Observatory for use at the Cassegrain focus of the Keck II telescope. ESI saw first light on August 29, 1999. ESI is a multi-mode instrument that enables the observer to seamlessly switch between three modes during an observation. The three modes of ESI are: An R=13,000-echellette mode; Low-dispersion prismatic mode; Direct imaging mode. ESI contains a unique flexure compensation system which reduces the small instrument flexure to negligible proportions. Long-exposure images on the sky show FWHM spot diameters of 34 microns (0.34") averaged over the entire field of view. These are the best non-AO images taken in the visible at Keck Observatory to date. Maximum efficiencies are measured to be 28% for the echellette mode and greater than 41% for low-dispersion prismatic mode including atmospheric, telescope and detector losses. In this paper we describe the instrument and its development. We also discuss the performance-testing and some observational results.Comment: 10 pages, 14 figures, 8tables, accepted for publication in PASP, 15 April 200

Antivortices due to competing orbital and paramagnetic pair-breaking effects

Thermodynamically stable vortex-antivortex structures in a quasi-two-dimensional superconductor in a tilted magnetic field are predicted. For this geometry, both orbital and spin pair-breaking effects exist, with their relative strength depending on the tilt angle \Theta. The spectrum of possible states contains as limits the ordinary vortex state (for large \Theta) and the Fulde-Ferrell-Larkin-Ovchinnikov state (for \Theta=0). The quasiclassical equations are solved near H_{c2} for arbitrary \Theta and it is shown that stable states with coexisting vortices and antivortices exist in a small interval close to \Theta=0. The results are compared with recent predictions of antivortices in mesoscopic samples.Comment: 11 pages, 3 figure

Dynamic adsorption characteristics of thin layered activated charcoal materials used in chemical protective overgarments

The efficiency of a thin layered activated charcoal material used in chemical protective overgarments has been evaluated. The study has been conducted with the aim to obtain protective materials with best characteristics considering resistance to benzene effect under dynamic conditions and to create a new filtration protection device. In order to evaluate dynamic adsorption characteristics of thin layered sorption materials, sophisticated dynamic gas chromatography method is used. The curves of benzene penetration are determined for sandwich materials, and sorption layers used in filtrating protective clothing shows that thin layered carbon sorption materials (type M00) have good protective properties as compared to other similar materials. The findings will help to create conditions for developing a functional model for producing a new protective overgarment in the near future

Antiferromagnetic Phases in the Fulde-Ferrell-Larkin-Ovchinnikov State of CeCoIn_5

The antiferromagnetic (AFM) order in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state is analyzed on the basis of a Ginzburg-Landau theory. To examine the possible AFM-FFLO state in CeCoIn_5, we focus on the incommensurate AFM order characterized by the wave vector Q = Q_{0} \pm q_inc with Q_0 =(\pi,\pi,\pi) and q_inc \parallel [110] or [1-10] in the tetragonal crystal structure. We formulate the two component Ginzburg-Landau theory and investigate the two degenerate incommensurate AFM order. We show that the pinning of AFM moment due to the FFLO nodal planes leads to multiple phases in magnetic fields along [100] or [010]. The phase diagrams for various coupling constants between the two order parameters are shown for the comparison with CeCoIn_5. Experimental results of the NMR and neutron scattering measurements are discussed.Comment: 6pages, Proceedings of ICHE2010, To appear in J. Phys. Soc. Jpn. Supp

Antiferromagnetic Order and \pi-triplet Pairing in the Fulde-Ferrell-Larkin-Ovchinnikov State

The antiferromagnetic Fulde-Ferrell-Larkin-Ovchinnikov (AFM-FFLO) state of coexisting d-wave FFLO superconductivity and incommensurate AFM order is studied on the basis of Bogoliubov-de Gennes (BdG) equations. We show that the incommensurate AFM order is stabilized in the FFLO state by the appearance of the Andreev bound state localized around the zeros of the FFLO order parameter. The AFM-FFLO state is further enhanced by the induced \pi-triplet superconductivity (pair density wave). The AFM order occurs in the FFLO state even when it is neither stable in the normal state nor in the BCS state. The order parameters of the AFM order, d-wave superconductivity, and \pi-triplet pairing are investigated by focusing on their spatial structures. Roles of the spin fluctuations beyond the BdG equations are discussed. Their relevance to the high-field superconducting phase of CeCoIn_5 is discussed.Comment: Typos are fixed. Published versio

Ginzburg-Landau Analysis for the Antiferromagnetic Order in the Fulde-Ferrell-Larkin-Ovchinnikov Superconductor

Incommensurate antiferromangetic (AFM) order in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconductor is investigated on the basis of the Ginzburg-Landau theory. We formulate the two component Ginzburg-Landau model to discuss two degenerate incommensurate AFM states in the tetragonal crystal structure. Owing to the broken translation symmetry in the FFLO state, a multiple phase diagram of single-q phase and double-q phase is obtained under the magnetic field along [100] or [010] direction. Magnetic properties in each phase are investigated and compared with the neutron scattering and NMR measurements for a heavy fermion superconductor CeCoIn_5. An ultrasonic measurement is proposed for a future experimental study to identify the AFM-FFLO state. The field orientation dependence of the AFM order in CeCoIn_5 is discussed.Comment: 8 page

SUSY GUTs under Siege : Proton Decay

SO(10) supersymmetric grand unified theories [SUSY GUTs] provide a beautiful framework for physics beyond the standard model. Experimental measurements of the three gauge couplings are consistent with unification at a scale $M_G \sim 3 \times 10^{16}$ GeV. In addition predictive models for fermion masses and mixing angles have been found which fit the low energy data, including the recent data for neutrino oscillations. SO(10) boundary conditions can be tested via the spectrum of superparticles. The simplest models also predict neutron and proton decay rates. In this paper we discuss nucleon decay rates and obtain reasonable upper bounds. A clear picture of the allowed SUSY spectra as constrained by nucleon decay is presented.Comment: 13 page

Theory of Fulde-Ferrell-Larkin-Ovchinnikov state of superconductors with and without inversion symmetry: Hubbard model approach

We study Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state of superconductors with and without inversion symmetry based on the Hubbard model on the square lattice near half-filling, using the random phase approximation. We show that center of mass momentum $Q$ tends to be parallel to $x$- or y-axis in the presence of inversion symmetry, while $Q$ vector is likely to be perpendicular to the magnetic field in the absence of inversion symmetry. We also clarify that $d+f$-wave pairing is favored and the hetero spin triplet $f$-wave state is present in the FFLO state unlike state in the superconductors only with the Rashba type spin-orbit coupling (RSOC) originating from the broken inversion symmetry. The triplet $f$-wave state is enhanced by magnetic field and the RSOC. This stems from the reduction of the spin susceptibilities by the magnetic field and the RSOC.Comment: 9 pages, 15 figures, 1 tabl